MySQL Drivers and Plugins
PHP offers several MySQL drivers and plugins for accessing and handling MySQL.
The differences and functionality of the MySQL extensions are described within the overview of this section.
Overview of the MySQL PHP drivers
Introduction
Depending on the version of PHP, there are either two or three PHP APIs for accessing the MySQL database. PHP 5 users can choose between the deprecated mysql extension, mysqli, or PDO_MySQL. PHP 7 removes the mysql extension, leaving only the latter two options.
This guide explains the terminology used to describe each API, information about choosing which API to use, and also information to help choose which MySQL library to use with the API.
Terminology overview
This section provides an introduction to the options available to you when developing a PHP application that needs to interact with a MySQL database.
What is an API?
An Application Programming Interface, or API, defines the classes, methods, functions and variables that your application will need to call in order to carry out its desired task. In the case of PHP applications that need to communicate with databases the necessary APIs are usually exposed via PHP extensions.
APIs can be procedural or object-oriented. With a procedural API you call functions to carry out tasks, with the object-oriented API you instantiate classes and then call methods on the resulting objects. Of the two the latter is usually the preferred interface, as it is more modern and leads to better organized code.
When writing PHP applications that need to connect to the MySQL server there are several API options available. This document discusses what is available and how to select the best solution for your application.
What is a Connector?
In the MySQL documentation, the term connector refers to a piece of software that allows your application to connect to the MySQL database server. MySQL provides connectors for a variety of languages, including PHP.
If your PHP application needs to communicate with a database server you will need to write PHP code to perform such activities as connecting to the database server, querying the database and other database-related functions. Software is required to provide the API that your PHP application will use, and also handle the communication between your application and the database server, possibly using other intermediate libraries where necessary. This software is known generically as a connector, as it allows your application to connect to a database server.
What is a Driver?
A driver is a piece of software designed to communicate with a specific type of database server. The driver may also call a library, such as the MySQL Client Library or the MySQL Native Driver. These libraries implement the low-level protocol used to communicate with the MySQL database server.
By way of an example, the PHP Data Objects (PDO) database abstraction layer may use one of several database-specific drivers. One of the drivers it has available is the PDO MYSQL driver, which allows it to interface with the MySQL server.
Sometimes people use the terms connector and driver interchangeably,
this can be confusing. In the MySQL-related documentation the term
driver
is reserved for software that provides
the database-specific part of a connector package.
What is an Extension?
In the PHP documentation you will come across another term -
extension. The PHP code consists of a core,
with optional extensions to the core functionality. PHP's
MySQL-related extensions, such as the mysqli
extension, and the mysql extension, are
implemented using the PHP extension framework.
An extension typically exposes an API to the PHP programmer, to allow its facilities to be used programmatically. However, some extensions which use the PHP extension framework do not expose an API to the PHP programmer.
The PDO MySQL driver extension, for example, does not expose an API to the PHP programmer, but provides an interface to the PDO layer above it.
The terms API and extension should not be taken to mean the same thing, as an extension may not necessarily expose an API to the programmer.
Choosing an API
PHP offers three different APIs to connect to MySQL. Below we show the APIs provided by the mysql, mysqli, and PDO extensions. Each code snippet creates a connection to a MySQL server running on "example.com" using the username "user" and the password "password". And a query is run to greet the user.
Example #1 Comparing the three MySQL APIs
<?php
// mysqli
$mysqli = new mysqli("example.com", "user", "password", "database");
$result = $mysqli->query("SELECT 'Hello, dear MySQL user!' AS _message FROM DUAL");
$row = $result->fetch_assoc();
echo htmlentities($row['_message']);
// PDO
$pdo = new PDO('mysql:host=example.com;dbname=database', 'user', 'password');
$statement = $pdo->query("SELECT 'Hello, dear MySQL user!' AS _message FROM DUAL");
$row = $statement->fetch(PDO::FETCH_ASSOC);
echo htmlentities($row['_message']);
// mysql
$c = mysql_connect("example.com", "user", "password");
mysql_select_db("database");
$result = mysql_query("SELECT 'Hello, dear MySQL user!' AS _message FROM DUAL");
$row = mysql_fetch_assoc($result);
echo htmlentities($row['_message']);
?>
Recommended API
It is recommended to use either the mysqli or PDO_MySQL extensions. It is not recommended to use the old mysql extension for new development, as it was deprecated in PHP 5.5.0 and was removed in PHP 7. A detailed feature comparison matrix is provided below. The overall performance of all three extensions is considered to be about the same. Although the performance of the extension contributes only a fraction of the total run time of a PHP web request. Often, the impact is as low as 0.1%.
Feature comparison
| ext/mysqli | PDO_MySQL | ext/mysql | |
|---|---|---|---|
| PHP version introduced | 5.0 | 5.1 | 2.0 |
| Included with PHP 5.x | Yes | Yes | Yes |
| Included with PHP 7.x | Yes | Yes | No |
| Development status | Active | Active | Maintenance only in 5.x; removed in 7.x |
| Lifecycle | Active | Active | Deprecated in 5.x; removed in 7.x |
| Recommended for new projects | Yes | Yes | No |
| OOP Interface | Yes | Yes | No |
| Procedural Interface | Yes | No | Yes |
| API supports non-blocking, asynchronous queries with mysqlnd | Yes | No | No |
| Persistent Connections | Yes | Yes | Yes |
| API supports Charsets | Yes | Yes | Yes |
| API supports server-side Prepared Statements | Yes | Yes | No |
| API supports client-side Prepared Statements | No | Yes | No |
| API supports Stored Procedures | Yes | Yes | No |
| API supports Multiple Statements | Yes | Most | No |
| API supports Transactions | Yes | Yes | No |
| Transactions can be controlled with SQL | Yes | Yes | Yes |
| Supports all MySQL 5.1+ functionality | Yes | Most | No |
Choosing a library
The mysqli, PDO_MySQL and mysql PHP extensions are lightweight wrappers on
top of a C client library. The extensions can either use the
mysqlnd library or the libmysqlclient
library. Choosing a library is a compile time decision.
The mysqlnd library is part of the PHP distribution since 5.3.0. It offers features like lazy connections and query caching, features that are not available with libmysqlclient, so using the built-in mysqlnd library is highly recommended. See the mysqlnd documentation for additional details, and a listing of features and functionality that it offers.
Example #1 Configure commands for using mysqlnd or libmysqlclient
// Recommended, compiles with mysqlnd $ ./configure --with-mysqli=mysqlnd --with-pdo-mysql=mysqlnd --with-mysql=mysqlnd // Alternatively recommended, compiles with mysqlnd as of PHP 5.4 $ ./configure --with-mysqli --with-pdo-mysql --with-mysql // Not recommended, compiles with libmysqlclient $ ./configure --with-mysqli=/path/to/mysql_config --with-pdo-mysql=/path/to/mysql_config --with-mysql=/path/to/mysql_config
Library feature comparison
It is recommended to use the mysqlnd library instead of the MySQL Client Server library (libmysqlclient). Both libraries are supported and constantly being improved.
| MySQL native driver (mysqlnd) | MySQL client server library (libmysqlclient) |
|
|---|---|---|
| Part of the PHP distribution | Yes | No |
| PHP version introduced | 5.3.0 | N/A |
| License | PHP License 3.01 | Dual-License |
| Development status | Active | Active |
| Lifecycle | No end announced | No end announced |
| PHP 5.4 and above; compile default (for all MySQL extensions) | Yes | No |
| PHP 5.3; compile default (for all MySQL extensions) | No | Yes |
| Compression protocol support | Yes (5.3.1+) | Yes |
| SSL support | Yes (5.3.3+) | Yes |
| Named pipe support | Yes (5.3.4+) | Yes |
| Non-blocking, asynchronous queries | Yes | No |
| Performance statistics | Yes | No |
| LOAD LOCAL INFILE respects the open_basedir directive | Yes | No |
| Uses PHP's native memory management system (e.g., follows PHP memory limits) | Yes | No |
| Return numeric column as double (COM_QUERY) | Yes | No |
| Return numeric column as string (COM_QUERY) | Yes | Yes |
| Plugin API | Yes | Limited |
| Read/Write splitting for MySQL Replication | Yes, with plugin | No |
| Load Balancing | Yes, with plugin | No |
| Fail over | Yes, with plugin | No |
| Lazy connections | Yes, with plugin | No |
| Query caching | Yes, with plugin | No |
| Transparent query manipulations (E.g., auto-EXPLAIN or monitoring) | Yes, with plugin | No |
| Automatic reconnect | No | Optional |
Concepts
Table of Contents
These concepts are specific to the MySQL drivers for PHP.
Buffered and Unbuffered queries
Queries are using the buffered mode by default. This means that query results are immediately transferred from the MySQL Server to PHP and then are kept in the memory of the PHP process. This allows additional operations like counting the number of rows, and moving (seeking) the current result pointer. It also allows issuing further queries on the same connection while working on the result set. The downside of the buffered mode is that larger result sets might require quite a lot memory. The memory will be kept occupied till all references to the result set are unset or the result set was explicitly freed, which will automatically happen during request end the latest. The terminology "store result" is also used for buffered mode, as the whole result set is stored at once.
Note:
When using libmysqlclient as library PHP's memory limit won't count the memory used for result sets unless the data is fetched into PHP variables. With mysqlnd the memory accounted for will include the full result set.
Unbuffered MySQL queries execute the query and then return a resource while the data is still waiting on the MySQL server for being fetched. This uses less memory on the PHP-side, but can increase the load on the server. Unless the full result set was fetched from the server no further queries can be sent over the same connection. Unbuffered queries can also be referred to as "use result".
Following these characteristics buffered queries should be used in cases where you expect only a limited result set or need to know the amount of returned rows before reading all rows. Unbuffered mode should be used when you expect larger results.
Because buffered queries are the default, the examples below will demonstrate how to execute unbuffered queries with each API.
Example #1 Unbuffered query example: mysqli
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
$uresult = $mysqli->query("SELECT Name FROM City", MYSQLI_USE_RESULT);
if ($uresult) {
while ($row = $uresult->fetch_assoc()) {
echo $row['Name'] . PHP_EOL;
}
}
$uresult->close();
?>
Example #2 Unbuffered query example: pdo_mysql
<?php
$pdo = new PDO("mysql:host=localhost;dbname=world", 'my_user', 'my_pass');
$pdo->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, false);
$uresult = $pdo->query("SELECT Name FROM City");
if ($uresult) {
while ($row = $uresult->fetch(PDO::FETCH_ASSOC)) {
echo $row['Name'] . PHP_EOL;
}
}
?>
Example #3 Unbuffered query example: mysql
<?php
$conn = mysql_connect("localhost", "my_user", "my_pass");
$db = mysql_select_db("world");
$uresult = mysql_unbuffered_query("SELECT Name FROM City");
if ($uresult) {
while ($row = mysql_fetch_assoc($uresult)) {
echo $row['Name'] . PHP_EOL;
}
}
?>
Character sets
Ideally a proper character set will be set at the server level, and doing this is described within the » Character Set Configuration section of the MySQL Server manual. Alternatively, each MySQL API offers a method to set the character set at runtime.
The character set and character escaping
The character set should be understood and defined, as it has an affect on every action, and includes security implications. For example, the escaping mechanism (e.g., mysqli_real_escape_string() for mysqli, mysql_real_escape_string() for mysql, and PDO::quote() for PDO_MySQL) will adhere to this setting. It is important to realize that these functions will not use the character set that is defined with a query, so for example the following will not have an effect on them:
Example #1 Problems with setting the character set with SQL
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
// Will NOT affect $mysqli->real_escape_string();
$mysqli->query("SET NAMES utf8");
// Will NOT affect $mysqli->real_escape_string();
$mysqli->query("SET CHARACTER SET utf8");
// But, this will affect $mysqli->real_escape_string();
$mysqli->set_charset('utf8');
// But, this will NOT affect it (utf-8 vs utf8) -- don't use dashes here
$mysqli->set_charset('utf-8');
?>
Below are examples that demonstrate how to properly alter the character set at runtime using each API.
Note: Possible UTF-8 confusion
Because character set names in MySQL do not contain dashes, the string "utf8" is valid in MySQL to set the character set to UTF-8. The string "utf-8" is not valid, as using "utf-8" will fail to change the character set.
Example #2 Setting the character set example: mysqli
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
printf("Initial character set: %s\n", $mysqli->character_set_name());
if (!$mysqli->set_charset('utf8')) {
printf("Error loading character set utf8: %s\n", $mysqli->error);
exit;
}
echo "New character set information:\n";
print_r( $mysqli->get_charset() );
?>
Example #3 Setting the character set example: pdo_mysql
Note: This only works as of PHP 5.3.6.
<?php
$pdo = new PDO("mysql:host=localhost;dbname=world;charset=utf8", 'my_user', 'my_pass');
?>
Example #4 Setting the character set example: mysql
<?php
$conn = mysql_connect("localhost", "my_user", "my_pass");
$db = mysql_select_db("world");
echo 'Initial character set: ' . mysql_client_encoding($conn) . "\n";
if (!mysql_set_charset('utf8', $conn)) {
echo "Error: Unable to set the character set.\n";
exit;
}
echo 'Your current character set is: ' . mysql_client_encoding($conn);
?>
MySQL Improved Extension
Introduction
The mysqli extension allows you to access the
functionality provided by MySQL 4.1 and above. More information about
the MySQL Database server can be found at
» http://www.mysql.com/
An overview of software available for using MySQL from PHP can be found at Overview
Documentation for MySQL can be found at » http://dev.mysql.com/doc/.
Parts of this documentation included from MySQL manual with permissions of Oracle Corporation.
Examples use either the » world or » sakila database, which are freely available.
Overview
This section provides an introduction to the options available to you when developing a PHP application that needs to interact with a MySQL database.
What is an API?
An Application Programming Interface, or API, defines the classes, methods, functions and variables that your application will need to call in order to carry out its desired task. In the case of PHP applications that need to communicate with databases the necessary APIs are usually exposed via PHP extensions.
APIs can be procedural or object-oriented. With a procedural API you call functions to carry out tasks, with the object-oriented API you instantiate classes and then call methods on the resulting objects. Of the two the latter is usually the preferred interface, as it is more modern and leads to better organized code.
When writing PHP applications that need to connect to the MySQL server there are several API options available. This document discusses what is available and how to select the best solution for your application.
What is a Connector?
In the MySQL documentation, the term connector refers to a piece of software that allows your application to connect to the MySQL database server. MySQL provides connectors for a variety of languages, including PHP.
If your PHP application needs to communicate with a database server you will need to write PHP code to perform such activities as connecting to the database server, querying the database and other database-related functions. Software is required to provide the API that your PHP application will use, and also handle the communication between your application and the database server, possibly using other intermediate libraries where necessary. This software is known generically as a connector, as it allows your application to connect to a database server.
What is a Driver?
A driver is a piece of software designed to communicate with a specific type of database server. The driver may also call a library, such as the MySQL Client Library or the MySQL Native Driver. These libraries implement the low-level protocol used to communicate with the MySQL database server.
By way of an example, the PHP Data Objects (PDO) database abstraction layer may use one of several database-specific drivers. One of the drivers it has available is the PDO MYSQL driver, which allows it to interface with the MySQL server.
Sometimes people use the terms connector and driver interchangeably,
this can be confusing. In the MySQL-related documentation the term
driver
is reserved for software that provides
the database-specific part of a connector package.
What is an Extension?
In the PHP documentation you will come across another term -
extension. The PHP code consists of a core,
with optional extensions to the core functionality. PHP's
MySQL-related extensions, such as the mysqli
extension, and the mysql extension, are
implemented using the PHP extension framework.
An extension typically exposes an API to the PHP programmer, to allow its facilities to be used programmatically. However, some extensions which use the PHP extension framework do not expose an API to the PHP programmer.
The PDO MySQL driver extension, for example, does not expose an API to the PHP programmer, but provides an interface to the PDO layer above it.
The terms API and extension should not be taken to mean the same thing, as an extension may not necessarily expose an API to the programmer.
What are the main PHP API offerings for using MySQL?
There are three main API options when considering connecting to a MySQL database server:
-
PHP's MySQL Extension
-
PHP's mysqli Extension
-
PHP Data Objects (PDO)
Each has its own advantages and disadvantages. The following discussion aims to give a brief introduction to the key aspects of each API.
What is PHP's MySQL Extension?
This is the original extension designed to allow you to develop PHP
applications that interact with a MySQL database. The
mysql extension provides a procedural interface
and is intended for use only with MySQL versions older than 4.1.3.
This extension can be used with versions of MySQL 4.1.3 or newer,
but not all of the latest MySQL server features will be available.
Note:
If you are using MySQL versions 4.1.3 or later it is strongly recommended that you use the
mysqliextension instead.
The mysql extension source code is located in the
PHP extension directory ext/mysql.
For further information on the mysql extension,
see MySQL (Original).
What is PHP's mysqli Extension?
The mysqli extension, or as it is sometimes
known, the MySQL improved extension, was
developed to take advantage of new features found in MySQL systems
versions 4.1.3 and newer. The mysqli extension is
included with PHP versions 5 and later.
The mysqli extension has a number of benefits,
the key enhancements over the mysql extension
being:
-
Object-oriented interface
-
Support for Prepared Statements
-
Support for Multiple Statements
-
Support for Transactions
-
Enhanced debugging capabilities
-
Embedded server support
Note:
If you are using MySQL versions 4.1.3 or later it is strongly recommended that you use this extension.
As well as the object-oriented interface the extension also provides a procedural interface.
The mysqli extension is built using the PHP
extension framework, its source code is located in the directory
ext/mysqli.
For further information on the mysqli extension,
see MySQLi.
What is PDO?
PHP Data Objects, or PDO, is a database abstraction layer specifically for PHP applications. PDO provides a consistent API for your PHP application regardless of the type of database server your application will connect to. In theory, if you are using the PDO API, you could switch the database server you used, from say Firebird to MySQL, and only need to make minor changes to your PHP code.
Other examples of database abstraction layers include JDBC for Java applications and DBI for Perl.
While PDO has its advantages, such as a clean, simple, portable API, its main disadvantage is that it doesn't allow you to use all of the advanced features that are available in the latest versions of MySQL server. For example, PDO does not allow you to use MySQL's support for Multiple Statements.
PDO is implemented using the PHP extension framework, its source code is located in the directory ext/pdo.
For further information on PDO, see the PDO.
What is the PDO MYSQL driver?
The PDO MYSQL driver is not an API as such, at least from the PHP programmer's perspective. In fact the PDO MYSQL driver sits in the layer below PDO itself and provides MySQL-specific functionality. The programmer still calls the PDO API, but PDO uses the PDO MYSQL driver to carry out communication with the MySQL server.
The PDO MYSQL driver is one of several available PDO drivers. Other PDO drivers available include those for the Firebird and PostgreSQL database servers.
The PDO MYSQL driver is implemented using the PHP extension framework. Its source code is located in the directory ext/pdo_mysql. It does not expose an API to the PHP programmer.
For further information on the PDO MYSQL driver, see MySQL (PDO).
What is PHP's MySQL Native Driver?
In order to communicate with the MySQL database server the
mysql extension, mysqli and
the PDO MYSQL driver each use a low-level library that implements
the required protocol. In the past, the only available library was
the MySQL Client Library, otherwise known as
libmysqlclient.
However, the interface presented by libmysqlclient was
not optimized for communication with PHP applications, as
libmysqlclient was originally designed with C
applications in mind. For this reason the MySQL Native Driver,
mysqlnd, was developed as an alternative to
libmysqlclient for PHP applications.
The mysql extension, the
mysqli extension and the PDO MySQL driver can
each be individually configured to use either
libmysqlclient or mysqlnd. As
mysqlnd is designed specifically to be utilised
in the PHP system it has numerous memory and speed enhancements over
libmysqlclient. You are strongly encouraged to take
advantage of these improvements.
Note:
The MySQL Native Driver can only be used with MySQL server versions 4.1.3 and later.
The MySQL Native Driver is implemented using the PHP extension framework. The source code is located in ext/mysqlnd. It does not expose an API to the PHP programmer.
Comparison of Features
The following table compares the functionality of the three main methods of connecting to MySQL from PHP:
| PHP's mysqli Extension | PDO (Using PDO MySQL Driver and MySQL Native Driver) | PHP's MySQL Extension | |
|---|---|---|---|
| PHP version introduced | 5.0 | 5.0 | Prior to 3.0 |
| Included with PHP 5.x | yes | yes | Yes |
| MySQL development status | Active development | Active development as of PHP 5.3 | Maintenance only |
| Recommended by MySQL for new projects | Yes - preferred option | Yes | No |
| API supports Charsets | Yes | Yes | No |
| API supports server-side Prepared Statements | Yes | Yes | No |
| API supports client-side Prepared Statements | No | Yes | No |
| API supports Stored Procedures | Yes | Yes | No |
| API supports Multiple Statements | Yes | Most | No |
| Supports all MySQL 4.1+ functionality | Yes | Most | No |
Quick start guide
Table of Contents
- Dual procedural and object-oriented interface
- Connections
- Executing statements
- Prepared Statements
- Stored Procedures
- Multiple Statements
- API support for transactions
- Metadata
This quick start guide will help with choosing and gaining familiarity with the PHP MySQL API.
This quick start gives an overview on the mysqli extension. Code examples are provided for all major aspects of the API. Database concepts are explained to the degree needed for presenting concepts specific to MySQL.
Required: A familiarity with the PHP programming language, the SQL language, and basic knowledge of the MySQL server.
Dual procedural and object-oriented interface
The mysqli extension features a dual interface. It supports the procedural and object-oriented programming paradigm.
Users migrating from the old mysql extension may prefer the procedural interface. The procedural interface is similar to that of the old mysql extension. In many cases, the function names differ only by prefix. Some mysqli functions take a connection handle as their first argument, whereas matching functions in the old mysql interface take it as an optional last argument.
Example #1 Easy migration from the old mysql extension
<?php
$mysqli = mysqli_connect("example.com", "user", "password", "database");
$res = mysqli_query($mysqli, "SELECT 'Please, do not use ' AS _msg FROM DUAL");
$row = mysqli_fetch_assoc($res);
echo $row['_msg'];
$mysql = mysql_connect("example.com", "user", "password");
mysql_select_db("test");
$res = mysql_query("SELECT 'the mysql extension for new developments.' AS _msg FROM DUAL", $mysql);
$row = mysql_fetch_assoc($res);
echo $row['_msg'];
?>
The above example will output:
Please, do not use the mysql extension for new developments.
The object-oriented interface
In addition to the classical procedural interface, users can choose to use the object-oriented interface. The documentation is organized using the object-oriented interface. The object-oriented interface shows functions grouped by their purpose, making it easier to get started. The reference section gives examples for both syntax variants.
There are no significant performance differences between the two interfaces. Users can base their choice on personal preference.
Example #2 Object-oriented and procedural interface
<?php
$mysqli = mysqli_connect("example.com", "user", "password", "database");
if (mysqli_connect_errno()) {
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$res = mysqli_query($mysqli, "SELECT 'A world full of ' AS _msg FROM DUAL");
$row = mysqli_fetch_assoc($res);
echo $row['_msg'];
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: " . $mysqli->connect_error;
}
$res = $mysqli->query("SELECT 'choices to please everybody.' AS _msg FROM DUAL");
$row = $res->fetch_assoc();
echo $row['_msg'];
?>
The above example will output:
A world full of choices to please everybody.
The object oriented interface is used for the quickstart because the reference section is organized that way.
Mixing styles
It is possible to switch between styles at any time. Mixing both styles is not recommended for code clarity and coding style reasons.
Example #3 Bad coding style
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: " . $mysqli->connect_error;
}
$res = mysqli_query($mysqli, "SELECT 'Possible but bad style.' AS _msg FROM DUAL");
if (!$res) {
echo "Failed to run query: (" . $mysqli->errno . ") " . $mysqli->error;
}
if ($row = $res->fetch_assoc()) {
echo $row['_msg'];
}
?>
The above example will output:
Possible but bad style.
See also
Connections
The MySQL server supports the use of different transport layers for connections. Connections use TCP/IP, Unix domain sockets or Windows named pipes.
The hostname localhost has a special meaning.
It is bound to the use of Unix domain sockets. It is not possible
to open a TCP/IP connection using the hostname localhost
you must use 127.0.0.1 instead.
Example #1 Special meaning of localhost
<?php
$mysqli = new mysqli("localhost", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
echo $mysqli->host_info . "\n";
$mysqli = new mysqli("127.0.0.1", "user", "password", "database", 3306);
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
echo $mysqli->host_info . "\n";
?>
The above example will output:
Localhost via UNIX socket 127.0.0.1 via TCP/IP
Connection parameter defaults
Depending on the connection function used, assorted parameters can be omitted. If a parameter is not provided, then the extension attempts to use the default values that are set in the PHP configuration file.
Example #2 Setting defaults
mysqli.default_host=192.168.2.27 mysqli.default_user=root mysqli.default_pw="" mysqli.default_port=3306 mysqli.default_socket=/tmp/mysql.sock
The resulting parameter values are then passed to the client library that is used by the extension. If the client library detects empty or unset parameters, then it may default to the library built-in values.
Built-in connection library defaults
If the host value is unset or empty, then the client library will
default to a Unix socket connection on localhost.
If socket is unset or empty, and a Unix socket connection is requested,
then a connection to the default socket on /tmp/mysql.sock
is attempted.
On Windows systems, the host name . is interpreted
by the client library as an attempt to open a Windows named pipe based
connection. In this case the socket parameter is interpreted as the pipe
name. If not given or empty, then the socket (pipe name) defaults to
\\.\pipe\MySQL.
If neither a Unix domain socket based not a Windows named pipe based connection
is to be established and the port parameter value is unset, the library
will default to port 3306.
The mysqlnd library and the MySQL Client Library (libmysqlclient) implement the same logic for determining defaults.
Connection options
Connection options are available to, for example, set init commands which are executed upon connect, or for requesting use of a certain charset. Connection options must be set before a network connection is established.
For setting a connection option, the connect operation has to be performed in three steps: creating a connection handle with mysqli_init(), setting the requested options using mysqli_options(), and establishing the network connection with mysqli_real_connect().
Connection pooling
The mysqli extension supports persistent database connections, which are a special kind of pooled connections. By default, every database connection opened by a script is either explicitly closed by the user during runtime or released automatically at the end of the script. A persistent connection is not. Instead it is put into a pool for later reuse, if a connection to the same server using the same username, password, socket, port and default database is opened. Reuse saves connection overhead.
Every PHP process is using its own mysqli connection pool. Depending on the web server deployment model, a PHP process may serve one or multiple requests. Therefore, a pooled connection may be used by one or more scripts subsequently.
Persistent connection
If a unused persistent connection for a given combination of host, username, password, socket, port and default database can not be found in the connection pool, then mysqli opens a new connection. The use of persistent connections can be enabled and disabled using the PHP directive mysqli.allow_persistent. The total number of connections opened by a script can be limited with mysqli.max_links. The maximum number of persistent connections per PHP process can be restricted with mysqli.max_persistent. Please note, that the web server may spawn many PHP processes.
A common complain about persistent connections is that their state is
not reset before reuse. For example, open and unfinished transactions are not
automatically rolled back. But also, authorization changes which happened
in the time between putting the connection into the pool and reusing it
are not reflected. This may be seen as an unwanted side-effect. On the contrary,
the name persistent may be understood as a promise
that the state is persisted.
The mysqli extension supports both interpretations of a persistent connection: state persisted, and state reset before reuse. The default is reset. Before a persistent connection is reused, the mysqli extension implicitly calls mysqli_change_user() to reset the state. The persistent connection appears to the user as if it was just opened. No artifacts from previous usages are visible.
The mysqli_change_user() function is an expensive operation.
For best performance, users may want to recompile the extension with the
compile flag MYSQLI_NO_CHANGE_USER_ON_PCONNECT being set.
It is left to the user to choose between safe behavior and best performance. Both are valid optimization goals. For ease of use, the safe behavior has been made the default at the expense of maximum performance.
See also
Executing statements
Statements can be executed with the mysqli_query(), mysqli_real_query() and mysqli_multi_query() functions. The mysqli_query() function is the most common, and combines the executing statement with a buffered fetch of its result set, if any, in one call. Calling mysqli_query() is identical to calling mysqli_real_query() followed by mysqli_store_result().
Example #1 Connecting to MySQL
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
if (!$mysqli->query("DROP TABLE IF EXISTS test") ||
!$mysqli->query("CREATE TABLE test(id INT)") ||
!$mysqli->query("INSERT INTO test(id) VALUES (1)")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
?>
Buffered result sets
After statement execution results can be retrieved at once to be buffered by the client or by read row by row. Client-side result set buffering allows the server to free resources associated with the statement results as early as possible. Generally speaking, clients are slow consuming result sets. Therefore, it is recommended to use buffered result sets. mysqli_query() combines statement execution and result set buffering.
PHP applications can navigate freely through buffered results. Navigation is fast because the result sets are held in client memory. Please, keep in mind that it is often easier to scale by client than it is to scale the server.
Example #2 Navigation through buffered results
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
if (!$mysqli->query("DROP TABLE IF EXISTS test") ||
!$mysqli->query("CREATE TABLE test(id INT)") ||
!$mysqli->query("INSERT INTO test(id) VALUES (1), (2), (3)")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
$res = $mysqli->query("SELECT id FROM test ORDER BY id ASC");
echo "Reverse order...\n";
for ($row_no = $res->num_rows - 1; $row_no >= 0; $row_no--) {
$res->data_seek($row_no);
$row = $res->fetch_assoc();
echo " id = " . $row['id'] . "\n";
}
echo "Result set order...\n";
$res->data_seek(0);
while ($row = $res->fetch_assoc()) {
echo " id = " . $row['id'] . "\n";
}
?>
The above example will output:
Reverse order...
id = 3
id = 2
id = 1
Result set order...
id = 1
id = 2
id = 3
Unbuffered result sets
If client memory is a short resource and freeing server resources as early as possible to keep server load low is not needed, unbuffered results can be used. Scrolling through unbuffered results is not possible before all rows have been read.
Example #3 Navigation through unbuffered results
<?php
$mysqli->real_query("SELECT id FROM test ORDER BY id ASC");
$res = $mysqli->use_result();
echo "Result set order...\n";
while ($row = $res->fetch_assoc()) {
echo " id = " . $row['id'] . "\n";
}
?>
Result set values data types
The mysqli_query(), mysqli_real_query()
and mysqli_multi_query() functions are used to execute
non-prepared statements. At the level of the MySQL Client Server Protocol,
the command COM_QUERY and the text protocol are used
for statement execution. With the text protocol, the MySQL server converts
all data of a result sets into strings before sending. This conversion is done
regardless of the SQL result set column data type. The mysql client libraries
receive all column values as strings. No further client-side casting is done
to convert columns back to their native types. Instead, all values are
provided as PHP strings.
Example #4 Text protocol returns strings by default
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
if (!$mysqli->query("DROP TABLE IF EXISTS test") ||
!$mysqli->query("CREATE TABLE test(id INT, label CHAR(1))") ||
!$mysqli->query("INSERT INTO test(id, label) VALUES (1, 'a')")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
$res = $mysqli->query("SELECT id, label FROM test WHERE id = 1");
$row = $res->fetch_assoc();
printf("id = %s (%s)\n", $row['id'], gettype($row['id']));
printf("label = %s (%s)\n", $row['label'], gettype($row['label']));
?>
The above example will output:
id = 1 (string) label = a (string)
It is possible to convert integer and float columns back to PHP numbers by setting the
MYSQLI_OPT_INT_AND_FLOAT_NATIVE connection option,
if using the mysqlnd library. If set, the mysqlnd library will
check the result set meta data column types and convert numeric SQL columns
to PHP numbers, if the PHP data type value range allows for it.
This way, for example, SQL INT columns are returned as integers.
Example #5 Native data types with mysqlnd and connection option
<?php
$mysqli = mysqli_init();
$mysqli->options(MYSQLI_OPT_INT_AND_FLOAT_NATIVE, 1);
$mysqli->real_connect("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
if (!$mysqli->query("DROP TABLE IF EXISTS test") ||
!$mysqli->query("CREATE TABLE test(id INT, label CHAR(1))") ||
!$mysqli->query("INSERT INTO test(id, label) VALUES (1, 'a')")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
$res = $mysqli->query("SELECT id, label FROM test WHERE id = 1");
$row = $res->fetch_assoc();
printf("id = %s (%s)\n", $row['id'], gettype($row['id']));
printf("label = %s (%s)\n", $row['label'], gettype($row['label']));
?>
The above example will output:
id = 1 (integer) label = a (string)
See also
Prepared Statements
The MySQL database supports prepared statements. A prepared statement or a parameterized statement is used to execute the same statement repeatedly with high efficiency.
Basic workflow
The prepared statement execution consists of two stages: prepare and execute. At the prepare stage a statement template is sent to the database server. The server performs a syntax check and initializes server internal resources for later use.
The MySQL server supports using anonymous, positional placeholder
with ?.
Example #1 First stage: prepare
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
/* Non-prepared statement */
if (!$mysqli->query("DROP TABLE IF EXISTS test") || !$mysqli->query("CREATE TABLE test(id INT)")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
/* Prepared statement, stage 1: prepare */
if (!($stmt = $mysqli->prepare("INSERT INTO test(id) VALUES (?)"))) {
echo "Prepare failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
?>
Prepare is followed by execute. During execute the client binds parameter values and sends them to the server. The server creates a statement from the statement template and the bound values to execute it using the previously created internal resources.
Example #2 Second stage: bind and execute
<?php
/* Prepared statement, stage 2: bind and execute */
$id = 1;
if (!$stmt->bind_param("i", $id)) {
echo "Binding parameters failed: (" . $stmt->errno . ") " . $stmt->error;
}
if (!$stmt->execute()) {
echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
}
?>
Repeated execution
A prepared statement can be executed repeatedly. Upon every execution the current value of the bound variable is evaluated and sent to the server. The statement is not parsed again. The statement template is not transferred to the server again.
Example #3 INSERT prepared once, executed multiple times
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
/* Non-prepared statement */
if (!$mysqli->query("DROP TABLE IF EXISTS test") || !$mysqli->query("CREATE TABLE test(id INT)")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
/* Prepared statement, stage 1: prepare */
if (!($stmt = $mysqli->prepare("INSERT INTO test(id) VALUES (?)"))) {
echo "Prepare failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
/* Prepared statement, stage 2: bind and execute */
$id = 1;
if (!$stmt->bind_param("i", $id)) {
echo "Binding parameters failed: (" . $stmt->errno . ") " . $stmt->error;
}
if (!$stmt->execute()) {
echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
}
/* Prepared statement: repeated execution, only data transferred from client to server */
for ($id = 2; $id < 5; $id++) {
if (!$stmt->execute()) {
echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
}
}
/* explicit close recommended */
$stmt->close();
/* Non-prepared statement */
$res = $mysqli->query("SELECT id FROM test");
var_dump($res->fetch_all());
?>
The above example will output:
array(4) {
[0]=>
array(1) {
[0]=>
string(1) "1"
}
[1]=>
array(1) {
[0]=>
string(1) "2"
}
[2]=>
array(1) {
[0]=>
string(1) "3"
}
[3]=>
array(1) {
[0]=>
string(1) "4"
}
}
Every prepared statement occupies server resources. Statements should be closed explicitly immediately after use. If not done explicitly, the statement will be closed when the statement handle is freed by PHP.
Using a prepared statement is not always the most efficient
way of executing a statement. A prepared statement executed only
once causes more client-server round-trips than a non-prepared statement.
This is why the SELECT is not run as a
prepared statement above.
Also, consider the use of the MySQL multi-INSERT SQL syntax for INSERTs. For the example, multi-INSERT requires less round-trips between the server and client than the prepared statement shown above.
Example #4 Less round trips using multi-INSERT SQL
<?php
if (!$mysqli->query("INSERT INTO test(id) VALUES (1), (2), (3), (4)")) {
echo "Multi-INSERT failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
?>
Result set values data types
The MySQL Client Server Protocol defines a different data transfer protocol
for prepared statements and non-prepared statements. Prepared statements
are using the so called binary protocol. The MySQL server sends result
set data "as is" in binary format. Results are not serialized into
strings before sending. The client libraries do not receive strings only.
Instead, they will receive binary data and try to convert the values into
appropriate PHP data types. For example, results from an SQL
INT column will be provided as PHP integer variables.
Example #5 Native datatypes
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
if (!$mysqli->query("DROP TABLE IF EXISTS test") ||
!$mysqli->query("CREATE TABLE test(id INT, label CHAR(1))") ||
!$mysqli->query("INSERT INTO test(id, label) VALUES (1, 'a')")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
$stmt = $mysqli->prepare("SELECT id, label FROM test WHERE id = 1");
$stmt->execute();
$res = $stmt->get_result();
$row = $res->fetch_assoc();
printf("id = %s (%s)\n", $row['id'], gettype($row['id']));
printf("label = %s (%s)\n", $row['label'], gettype($row['label']));
?>
The above example will output:
id = 1 (integer) label = a (string)
This behavior differs from non-prepared statements. By default, non-prepared statements return all results as strings. This default can be changed using a connection option. If the connection option is used, there are no differences.
Fetching results using bound variables
Results from prepared statements can either be retrieved by binding output variables, or by requesting a mysqli_result object.
Output variables must be bound after statement execution. One variable must be bound for every column of the statements result set.
Example #6 Output variable binding
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
if (!$mysqli->query("DROP TABLE IF EXISTS test") ||
!$mysqli->query("CREATE TABLE test(id INT, label CHAR(1))") ||
!$mysqli->query("INSERT INTO test(id, label) VALUES (1, 'a')")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!($stmt = $mysqli->prepare("SELECT id, label FROM test"))) {
echo "Prepare failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!$stmt->execute()) {
echo "Execute failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
$out_id = NULL;
$out_label = NULL;
if (!$stmt->bind_result($out_id, $out_label)) {
echo "Binding output parameters failed: (" . $stmt->errno . ") " . $stmt->error;
}
while ($stmt->fetch()) {
printf("id = %s (%s), label = %s (%s)\n", $out_id, gettype($out_id), $out_label, gettype($out_label));
}
?>
The above example will output:
id = 1 (integer), label = a (string)
Prepared statements return unbuffered result sets by default.
The results of the statement are not implicitly fetched and transferred
from the server to the client for client-side buffering. The result set
takes server resources until all results have been fetched by the client.
Thus it is recommended to consume results timely. If a client fails to fetch all
results or the client closes the statement before having fetched all data,
the data has to be fetched implicitly by mysqli.
It is also possible to buffer the results of a prepared statement using mysqli_stmt_store_result().
Fetching results using mysqli_result interface
Instead of using bound results, results can also be retrieved through the mysqli_result interface. mysqli_stmt_get_result() returns a buffered result set.
Example #7 Using mysqli_result to fetch results
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
if (!$mysqli->query("DROP TABLE IF EXISTS test") ||
!$mysqli->query("CREATE TABLE test(id INT, label CHAR(1))") ||
!$mysqli->query("INSERT INTO test(id, label) VALUES (1, 'a')")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!($stmt = $mysqli->prepare("SELECT id, label FROM test ORDER BY id ASC"))) {
echo "Prepare failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!$stmt->execute()) {
echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
}
if (!($res = $stmt->get_result())) {
echo "Getting result set failed: (" . $stmt->errno . ") " . $stmt->error;
}
var_dump($res->fetch_all());
?>
The above example will output:
array(1) {
[0]=>
array(2) {
[0]=>
int(1)
[1]=>
string(1) "a"
}
}
Using the mysqli_result interface offers the additional benefit of flexible client-side result set navigation.
Example #8 Buffered result set for flexible read out
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
if (!$mysqli->query("DROP TABLE IF EXISTS test") ||
!$mysqli->query("CREATE TABLE test(id INT, label CHAR(1))") ||
!$mysqli->query("INSERT INTO test(id, label) VALUES (1, 'a'), (2, 'b'), (3, 'c')")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!($stmt = $mysqli->prepare("SELECT id, label FROM test"))) {
echo "Prepare failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!$stmt->execute()) {
echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
}
if (!($res = $stmt->get_result())) {
echo "Getting result set failed: (" . $stmt->errno . ") " . $stmt->error;
}
for ($row_no = ($res->num_rows - 1); $row_no >= 0; $row_no--) {
$res->data_seek($row_no);
var_dump($res->fetch_assoc());
}
$res->close();
?>
The above example will output:
array(2) {
["id"]=>
int(3)
["label"]=>
string(1) "c"
}
array(2) {
["id"]=>
int(2)
["label"]=>
string(1) "b"
}
array(2) {
["id"]=>
int(1)
["label"]=>
string(1) "a"
}
Escaping and SQL injection
Bound variables are sent to the server separately from the query and thus cannot interfere with it. The server uses these values directly at the point of execution, after the statement template is parsed. Bound parameters do not need to be escaped as they are never substituted into the query string directly. A hint must be provided to the server for the type of bound variable, to create an appropriate conversion. See the mysqli_stmt_bind_param() function for more information.
Such a separation sometimes considered as the only security feature to prevent SQL injection, but the same degree of security can be achieved with non-prepared statements, if all the values are formatted correctly. It should be noted that correct formatting is not the same as escaping and involves more logic than simple escaping. Thus, prepared statements are simply a more convenient and less error-prone approach to this element of database security.
Client-side prepared statement emulation
The API does not include emulation for client-side prepared statement emulation.
Quick prepared - non-prepared statement comparison
The table below compares server-side prepared and non-prepared statements.
| Prepared Statement | Non-prepared statement | |
|---|---|---|
| Client-server round trips, SELECT, single execution | 2 | 1 |
| Statement string transferred from client to server | 1 | 1 |
| Client-server round trips, SELECT, repeated (n) execution | 1 + n | n |
| Statement string transferred from client to server | 1 template, n times bound parameter, if any | n times together with parameter, if any |
| Input parameter binding API | Yes, automatic input escaping | No, manual input escaping |
| Output variable binding API | Yes | No |
| Supports use of mysqli_result API | Yes, use mysqli_stmt_get_result() | Yes |
| Buffered result sets | Yes, use mysqli_stmt_get_result() or binding with mysqli_stmt_store_result() | Yes, default of mysqli_query() |
| Unbuffered result sets | Yes, use output binding API | Yes, use mysqli_real_query() with mysqli_use_result() |
| MySQL Client Server protocol data transfer flavor | Binary protocol | Text protocol |
| Result set values SQL data types | Preserved when fetching | Converted to string or preserved when fetching |
| Supports all SQL statements | Recent MySQL versions support most but not all | Yes |
See also
Stored Procedures
The MySQL database supports stored procedures. A stored procedure is a
subroutine stored in the database catalog. Applications can call and
execute the stored procedure. The CALL
SQL statement is used to execute a stored procedure.
Parameter
Stored procedures can have IN,
INOUT and OUT parameters,
depending on the MySQL version. The mysqli interface has no special
notion for the different kinds of parameters.
IN parameter
Input parameters are provided with the CALL statement.
Please, make sure values are escaped correctly.
Example #1 Calling a stored procedure
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
if (!$mysqli->query("DROP TABLE IF EXISTS test") || !$mysqli->query("CREATE TABLE test(id INT)")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!$mysqli->query("DROP PROCEDURE IF EXISTS p") ||
!$mysqli->query("CREATE PROCEDURE p(IN id_val INT) BEGIN INSERT INTO test(id) VALUES(id_val); END;")) {
echo "Stored procedure creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!$mysqli->query("CALL p(1)")) {
echo "CALL failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!($res = $mysqli->query("SELECT id FROM test"))) {
echo "SELECT failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
var_dump($res->fetch_assoc());
?>
The above example will output:
array(1) {
["id"]=>
string(1) "1"
}
INOUT/OUT parameter
The values of INOUT/OUT
parameters are accessed using session variables.
Example #2 Using session variables
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
if (!$mysqli->query("DROP PROCEDURE IF EXISTS p") ||
!$mysqli->query('CREATE PROCEDURE p(OUT msg VARCHAR(50)) BEGIN SELECT "Hi!" INTO msg; END;')) {
echo "Stored procedure creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!$mysqli->query("SET @msg = ''") || !$mysqli->query("CALL p(@msg)")) {
echo "CALL failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!($res = $mysqli->query("SELECT @msg as _p_out"))) {
echo "Fetch failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
$row = $res->fetch_assoc();
echo $row['_p_out'];
?>
The above example will output:
Hi!
Application and framework developers may be able to provide a more convenient API using a mix of session variables and databased catalog inspection. However, please note the possible performance impact of a custom solution based on catalog inspection.
Handling result sets
Stored procedures can return result sets. Result sets returned from a stored procedure cannot be fetched correctly using mysqli_query(). The mysqli_query() function combines statement execution and fetching the first result set into a buffered result set, if any. However, there are additional stored procedure result sets hidden from the user which cause mysqli_query() to fail returning the user expected result sets.
Result sets returned from a stored procedure are fetched using
mysqli_real_query() or mysqli_multi_query().
Both functions allow fetching any number of result sets returned by a
statement, such as CALL. Failing to fetch all
result sets returned by a stored procedure causes an error.
Example #3 Fetching results from stored procedures
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
if (!$mysqli->query("DROP TABLE IF EXISTS test") ||
!$mysqli->query("CREATE TABLE test(id INT)") ||
!$mysqli->query("INSERT INTO test(id) VALUES (1), (2), (3)")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!$mysqli->query("DROP PROCEDURE IF EXISTS p") ||
!$mysqli->query('CREATE PROCEDURE p() READS SQL DATA BEGIN SELECT id FROM test; SELECT id + 1 FROM test; END;')) {
echo "Stored procedure creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!$mysqli->multi_query("CALL p()")) {
echo "CALL failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
do {
if ($res = $mysqli->store_result()) {
printf("---\n");
var_dump($res->fetch_all());
$res->free();
} else {
if ($mysqli->errno) {
echo "Store failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
}
} while ($mysqli->more_results() && $mysqli->next_result());
?>
The above example will output:
---
array(3) {
[0]=>
array(1) {
[0]=>
string(1) "1"
}
[1]=>
array(1) {
[0]=>
string(1) "2"
}
[2]=>
array(1) {
[0]=>
string(1) "3"
}
}
---
array(3) {
[0]=>
array(1) {
[0]=>
string(1) "2"
}
[1]=>
array(1) {
[0]=>
string(1) "3"
}
[2]=>
array(1) {
[0]=>
string(1) "4"
}
}
Use of prepared statements
No special handling is required when using the prepared statement
interface for fetching results from the same stored procedure as above.
The prepared statement and non-prepared statement interfaces are similar.
Please note, that not every MYSQL server version may support
preparing the CALL SQL statement.
Example #4 Stored Procedures and Prepared Statements
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
if (!$mysqli->query("DROP TABLE IF EXISTS test") ||
!$mysqli->query("CREATE TABLE test(id INT)") ||
!$mysqli->query("INSERT INTO test(id) VALUES (1), (2), (3)")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!$mysqli->query("DROP PROCEDURE IF EXISTS p") ||
!$mysqli->query('CREATE PROCEDURE p() READS SQL DATA BEGIN SELECT id FROM test; SELECT id + 1 FROM test; END;')) {
echo "Stored procedure creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!($stmt = $mysqli->prepare("CALL p()"))) {
echo "Prepare failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!$stmt->execute()) {
echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
}
do {
if ($res = $stmt->get_result()) {
printf("---\n");
var_dump(mysqli_fetch_all($res));
mysqli_free_result($res);
} else {
if ($stmt->errno) {
echo "Store failed: (" . $stmt->errno . ") " . $stmt->error;
}
}
} while ($stmt->more_results() && $stmt->next_result());
?>
Of course, use of the bind API for fetching is supported as well.
Example #5 Stored Procedures and Prepared Statements using bind API
<?php
if (!($stmt = $mysqli->prepare("CALL p()"))) {
echo "Prepare failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
if (!$stmt->execute()) {
echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
}
do {
$id_out = NULL;
if (!$stmt->bind_result($id_out)) {
echo "Bind failed: (" . $stmt->errno . ") " . $stmt->error;
}
while ($stmt->fetch()) {
echo "id = $id_out\n";
}
} while ($stmt->more_results() && $stmt->next_result());
?>
See also
- mysqli::query()
- mysqli::multi_query()
- mysqli_result::next-result()
- mysqli_result::more-results()
Multiple Statements
MySQL optionally allows having multiple statements in one statement string. Sending multiple statements at once reduces client-server round trips but requires special handling.
Multiple statements or multi queries must be executed with mysqli_multi_query(). The individual statements of the statement string are separated by semicolon. Then, all result sets returned by the executed statements must be fetched.
The MySQL server allows having statements that do return result sets and statements that do not return result sets in one multiple statement.
Example #1 Multiple Statements
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
if (!$mysqli->query("DROP TABLE IF EXISTS test") || !$mysqli->query("CREATE TABLE test(id INT)")) {
echo "Table creation failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
$sql = "SELECT COUNT(*) AS _num FROM test; ";
$sql.= "INSERT INTO test(id) VALUES (1); ";
$sql.= "SELECT COUNT(*) AS _num FROM test; ";
if (!$mysqli->multi_query($sql)) {
echo "Multi query failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
do {
if ($res = $mysqli->store_result()) {
var_dump($res->fetch_all(MYSQLI_ASSOC));
$res->free();
}
} while ($mysqli->more_results() && $mysqli->next_result());
?>
The above example will output:
array(1) {
[0]=>
array(1) {
["_num"]=>
string(1) "0"
}
}
array(1) {
[0]=>
array(1) {
["_num"]=>
string(1) "1"
}
}
Security considerations
The API functions mysqli_query() and
mysqli_real_query() do not set a connection flag necessary
for activating multi queries in the server. An extra API call is used for
multiple statements to reduce the likeliness of accidental SQL injection
attacks. An attacker may try to add statements such as
; DROP DATABASE mysql or ; SELECT SLEEP(999).
If the attacker succeeds in adding SQL to the statement string but
mysqli_multi_query is not used, the server will not
execute the second, injected and malicious SQL statement.
Example #2 SQL Injection
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
$res = $mysqli->query("SELECT 1; DROP TABLE mysql.user");
if (!$res) {
echo "Error executing query: (" . $mysqli->errno . ") " . $mysqli->error;
}
?>
The above example will output:
Error executing query: (1064) You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DROP TABLE mysql.user' at line 1
Prepared statements
Use of the multiple statement with prepared statements is not supported.
See also
- mysqli::query()
- mysqli::multi_query()
- mysqli_result::next-result()
- mysqli_result::more-results()
API support for transactions
The MySQL server supports transactions depending on the storage engine used. Since MySQL 5.5, the default storage engine is InnoDB. InnoDB has full ACID transaction support.
Transactions can either be controlled using SQL or API calls. It is recommended to use API calls for enabling and disabling the auto commit mode and for committing and rolling back transactions.
Example #1 Setting auto commit mode with SQL and through the API
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
/* Recommended: using API to control transactional settings */
$mysqli->autocommit(false);
/* Won't be monitored and recognized by the replication and the load balancing plugin */
if (!$mysqli->query('SET AUTOCOMMIT = 0')) {
echo "Query failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
?>
Optional feature packages, such as the replication and load balancing plugin, can easily monitor API calls. The replication plugin offers transaction aware load balancing, if transactions are controlled with API calls. Transaction aware load balancing is not available if SQL statements are used for setting auto commit mode, committing or rolling back a transaction.
Example #2 Commit and rollback
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
$mysqli->autocommit(false);
$mysqli->query("INSERT INTO test(id) VALUES (1)");
$mysqli->rollback();
$mysqli->query("INSERT INTO test(id) VALUES (2)");
$mysqli->commit();
?>
Please note, that the MySQL server cannot roll back all statements. Some statements cause an implicit commit.
See also
- mysqli::autocommit()
- mysqli_result::commit()
- mysqli_result::rollback()
Metadata
A MySQL result set contains metadata. The metadata describes the columns
found in the result set. All metadata sent by MySQL is accessible
through the mysqli interface.
The extension performs no or negligible changes to the
information it receives.
Differences between MySQL server versions are not aligned.
Meta data is access through the mysqli_result interface.
Example #1 Accessing result set meta data
<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}
$res = $mysqli->query("SELECT 1 AS _one, 'Hello' AS _two FROM DUAL");
var_dump($res->fetch_fields());
?>
The above example will output:
array(2) {
[0]=>
object(stdClass)#3 (13) {
["name"]=>
string(4) "_one"
["orgname"]=>
string(0) ""
["table"]=>
string(0) ""
["orgtable"]=>
string(0) ""
["def"]=>
string(0) ""
["db"]=>
string(0) ""
["catalog"]=>
string(3) "def"
["max_length"]=>
int(1)
["length"]=>
int(1)
["charsetnr"]=>
int(63)
["flags"]=>
int(32897)
["type"]=>
int(8)
["decimals"]=>
int(0)
}
[1]=>
object(stdClass)#4 (13) {
["name"]=>
string(4) "_two"
["orgname"]=>
string(0) ""
["table"]=>
string(0) ""
["orgtable"]=>
string(0) ""
["def"]=>
string(0) ""
["db"]=>
string(0) ""
["catalog"]=>
string(3) "def"
["max_length"]=>
int(5)
["length"]=>
int(5)
["charsetnr"]=>
int(8)
["flags"]=>
int(1)
["type"]=>
int(253)
["decimals"]=>
int(31)
}
}
Prepared statements
Meta data of result sets created using prepared statements are accessed the same way. A suitable mysqli_result handle is returned by mysqli_stmt_result_metadata().
Example #2 Prepared statements metadata
<?php
$stmt = $mysqli->prepare("SELECT 1 AS _one, 'Hello' AS _two FROM DUAL");
$stmt->execute();
$res = $stmt->result_metadata();
var_dump($res->fetch_fields());
?>
See also
Installing/Configuring
Table of Contents
Requirements
In order to have these functions available, you must compile PHP with support for the mysqli extension.
MySQL 8
When running a PHP version before 7.1.16, or PHP 7.2 before 7.2.4, set MySQL 8 Server's default password plugin to mysql_native_password or else you will see errors similar to The server requested authentication method unknown to the client [caching_sha2_password] even when caching_sha2_password is not used.
This is because MySQL 8 defaults to caching_sha2_password, a plugin that is
not recognized by the older PHP (mysqlnd) releases. Instead, change it by
setting default_authentication_plugin=mysql_native_password
in my.cnf. The caching_sha2_password
plugin will be supported in a future PHP release. In the meantime, the
mysql_xdevapi extension does
support it.
Installation
The mysqli extension was introduced with PHP version
5.0.0. The MySQL Native Driver was included in PHP version 5.3.0.
Installation on Linux
The common Unix distributions include binary versions of PHP that can be installed. Although these binary versions are typically built with support for the MySQL extensions, the extension libraries themselves may need to be installed using an additional package. Check the package manager that comes with your chosen distribution for availability.
For example, on Ubuntu the php5-mysql package installs
the ext/mysql, ext/mysqli, and pdo_mysql PHP extensions. On CentOS,
the php-mysql package also installs these three
PHP extensions.
Alternatively, you can compile this extension yourself. Building PHP from source allows you to specify the MySQL extensions you want to use, as well as your choice of client library for each extension.
The MySQL Native Driver is the recommended client library option, as it results in improved performance and gives access to features not available when using the MySQL Client Library. Refer to What is PHP's MySQL Native Driver? for a brief overview of the advantages of MySQL Native Driver.
The /path/to/mysql_config represents the location of
the mysql_config program that comes with MySQL
Server.
| PHP Version | Default | Configure Options: mysqlnd | Configure Options: libmysqlclient |
Changelog |
|---|---|---|---|---|
| 5.4.x and above | mysqlnd | --with-mysqli | --with-mysqli=/path/to/mysql_config | mysqlnd is the default |
| 5.3.x | libmysqlclient | --with-mysqli=mysqlnd | --with-mysqli=/path/to/mysql_config | mysqlnd is supported |
| 5.0.x, 5.1.x, 5.2.x | libmysqlclient | Not Available | --with-mysqli=/path/to/mysql_config | mysqlnd is not supported |
Note that it is possible to freely mix MySQL extensions and client
libraries. For example, it is possible to enable the MySQL extension
to use the MySQL Client Library (libmysqlclient), while configuring the
mysqli extension to use the MySQL Native Driver.
However, all permutations of extension and client library are
possible.
Installation on Windows Systems
On Windows, PHP is most commonly installed using the binary installer.
PHP 5.3.0 and newer
On Windows, for PHP versions 5.3 and newer, the
mysqli extension is enabled and
uses the MySQL Native Driver by default. This means you don't need to
worry about configuring access
to libmysql.dll.
PHP 5.0, 5.1, 5.2
On these old unsupported PHP versions (PHP 5.2 reached EOL on '6 Jan 2011'),
additional configuration procedures are
required to enable mysqli and specify the client
library you want it to use.
The mysqli extension is not
enabled by default, so the php_mysqli.dll DLL
must be enabled inside of php.ini. In order to do this you need to
find the php.ini file (typically located in
c:\php), and make sure you remove the comment
(semi-colon) from the start of the line
extension=php_mysqli.dll, in the section marked
[PHP_MYSQLI].
Also, if you want to use the MySQL Client Library with
mysqli, you need to make sure PHP can access the
client library file. The MySQL Client Library is included as a file
named libmysql.dll in the Windows PHP
distribution. This file needs to be available in the Windows system's
PATH environment variable, so that it can be
successfully loaded. See the FAQ titled
"How do I add my PHP
directory to the PATH on Windows" for information on how to do
this. Copying libmysql.dll to the Windows system
directory (typically c:\Windows\system) also
works, as the system directory is by default in the system's
PATH. However, this practice is strongly discouraged.
As with enabling any PHP extension (such as
php_mysqli.dll), the PHP directive
extension_dir should be set
to the directory where the PHP extensions are located. See also the
Manual Windows Installation
Instructions. An example extension_dir
value for PHP 5 is c:\php\ext.
Note:
If when starting the web server an error similar to the following occurs:
"Unable to load dynamic library './php_mysqli.dll'", this is because php_mysqli.dll and/or libmysql.dll cannot be found by the system.
Runtime Configuration
The behaviour of these functions is affected by settings in php.ini.
| Name | Default | Changeable | Changelog |
|---|---|---|---|
| mysqli.allow_local_infile | "0" | PHP_INI_SYSTEM | Available as of PHP 5.2.4. Before PHP 7.2.16 and 7.3.3 the default was "1". |
| mysqli.local_infile_directory | PHP_INI_SYSTEM | ||
| mysqli.allow_persistent | "1" | PHP_INI_SYSTEM | Available as of PHP 5.3.0. |
| mysqli.max_persistent | "-1" | PHP_INI_SYSTEM | Available as of PHP 5.3.0. |
| mysqli.max_links | "-1" | PHP_INI_SYSTEM | |
| mysqli.default_port | "3306" | PHP_INI_ALL | |
| mysqli.default_socket | NULL | PHP_INI_ALL | |
| mysqli.default_host | NULL | PHP_INI_ALL | |
| mysqli.default_user | NULL | PHP_INI_ALL | |
| mysqli.default_pw | NULL | PHP_INI_ALL | |
| mysqli.reconnect | "0" | PHP_INI_SYSTEM | |
| mysqli.rollback_on_cached_plink | TRUE | PHP_INI_SYSTEM | Available as of PHP 5.6.0. |
For further details and definitions of the preceding PHP_INI_* constants, see the chapter on configuration changes.
Here's a short explanation of the configuration directives.
-
mysqli.allow_local_infileinteger -
Allow accessing, from PHP's perspective, local files with LOAD DATA statements
-
mysqli.local_infile_directorystring -
Allows restricting LOCAL DATA loading to files located in this designated directory.
-
mysqli.allow_persistentinteger -
Enable the ability to create persistent connections using mysqli_connect().
-
mysqli.max_persistentinteger -
Maximum of persistent connections that can be made. Set to 0 for unlimited.
-
mysqli.max_linksinteger -
The maximum number of MySQL connections per process.
-
mysqli.default_portinteger -
The default TCP port number to use when connecting to the database server if no other port is specified. If no default is specified, the port will be obtained from the
MYSQL_TCP_PORTenvironment variable, themysql-tcpentry in /etc/services or the compile-timeMYSQL_PORTconstant, in that order. Win32 will only use theMYSQL_PORTconstant. -
mysqli.default_socketstring -
The default socket name to use when connecting to a local database server if no other socket name is specified.
-
mysqli.default_hoststring -
The default server host to use when connecting to the database server if no other host is specified. Doesn't apply in safe mode.
-
mysqli.default_userstring -
The default user name to use when connecting to the database server if no other name is specified. Doesn't apply in safe mode.
-
mysqli.default_pwstring -
The default password to use when connecting to the database server if no other password is specified. Doesn't apply in safe mode.
-
mysqli.reconnectinteger -
Automatically reconnect if the connection was lost.
Note: This php.ini setting is ignored by the mysqlnd driver.
-
mysqli.rollback_on_cached_plinkbool -
If this option is enabled, closing a persistent connection will rollback any pending transactions of this connection before it is put back into the persistent connection pool. Otherwise, pending transactions will be rolled back only when the connection is reused, or when it is actually closed.
Users cannot set MYSQL_OPT_READ_TIMEOUT through an API
call or runtime configuration setting. Note that if it were possible there
would be differences between how libmysqlclient and
streams would interpret the value of MYSQL_OPT_READ_TIMEOUT.
Resource Types
This extension has no resource types defined.
The mysqli Extension and Persistent Connections
Persistent connection support was introduced in PHP 5.3 for the
mysqli extension. Support was already present in
PDO MYSQL and ext/mysql. The idea behind persistent connections is
that a connection between a client process and a database can be
reused by a client process, rather than being created and destroyed
multiple times. This reduces the overhead of creating fresh
connections every time one is required, as unused connections are
cached and ready to be reused.
Unlike the mysql extension, mysqli does not provide a separate function
for opening persistent connections. To open a persistent connection you
must prepend p: to the hostname when connecting.
The problem with persistent connections is that they can be left in
unpredictable states by clients. For example, a table lock might be
activated before a client terminates unexpectedly. A new client
process reusing this persistent connection will get the connection
as is
. Any cleanup would need to be done by the new
client process before it could make good use of the persistent
connection, increasing the burden on the programmer.
The persistent connection of the mysqli extension
however provides built-in cleanup handling code. The cleanup carried
out by mysqli includes:
-
Rollback active transactions
-
Close and drop temporary tables
-
Unlock tables
-
Reset session variables
-
Close prepared statements (always happens with PHP)
-
Close handler
-
Release locks acquired with GET_LOCK()
This ensures that persistent connections are in a clean state on return from the connection pool, before the client process uses them.
The mysqli extension does this cleanup by
automatically calling the C-API function
mysql_change_user().
The automatic cleanup feature has advantages and disadvantages though. The advantage is that the programmer no longer needs to worry about adding cleanup code, as it is called automatically. However, the disadvantage is that the code could potentially be a little slower, as the code to perform the cleanup needs to run each time a connection is returned from the connection pool.
It is possible to switch off the automatic cleanup code, by compiling
PHP with
MYSQLI_NO_CHANGE_USER_ON_PCONNECT
defined.
Note:
The
mysqliextension supports persistent connections when using either MySQL Native Driver or MySQL Client Library.
Predefined Constants
The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
MYSQLI_READ_DEFAULT_GROUP-
Read options from the named group from my.cnf or the file specified with
MYSQLI_READ_DEFAULT_FILE MYSQLI_READ_DEFAULT_FILE-
Read options from the named option file instead of from my.cnf
MYSQLI_OPT_CONNECT_TIMEOUT-
Connect timeout in seconds
MYSQLI_OPT_LOCAL_INFILE-
Enables command
LOAD LOCAL INFILE MYSQLI_OPT_INT_AND_FLOAT_NATIVE-
Convert integer and float columns back to PHP numbers. Only valid for mysqlnd. Available since PHP 5.3.0.
MYSQLI_OPT_NET_CMD_BUFFER_SIZE-
The size of the internal command/network buffer. Only valid for mysqlnd. Available since PHP 5.3.0.
MYSQLI_OPT_NET_READ_BUFFER_SIZE-
Maximum read chunk size in bytes when reading the body of a MySQL command packet. Only valid for mysqlnd. Available since PHP 5.3.0.
MYSQLI_OPT_SSL_VERIFY_SERVER_CERT-
Available since PHP 5.3.0. (MySQL 5.1.10 and up)
MYSQLI_INIT_COMMAND-
Command to execute when connecting to MySQL server. Will automatically be re-executed when reconnecting.
MYSQLI_CLIENT_SSL-
Use SSL (encrypted protocol). This option should not be set by application programs; it is set internally in the MySQL client library
MYSQLI_CLIENT_COMPRESS-
Use compression protocol
MYSQLI_CLIENT_INTERACTIVE-
Allow
interactive_timeoutseconds (instead ofwait_timeoutseconds) of inactivity before closing the connection. The client's sessionwait_timeoutvariable will be set to the value of the sessioninteractive_timeoutvariable. MYSQLI_CLIENT_IGNORE_SPACE-
Allow spaces after function names. Makes all functions names reserved words.
MYSQLI_CLIENT_NO_SCHEMA-
Don't allow the
db_name.tbl_name.col_namesyntax. MYSQLI_CLIENT_MULTI_QUERIES-
Allows multiple semicolon-delimited queries in a single mysqli_query() call.
MYSQLI_STORE_RESULT-
For using buffered resultsets
MYSQLI_USE_RESULT-
For using unbuffered resultsets
MYSQLI_ASSOC-
Columns are returned into the array having the fieldname as the array index.
MYSQLI_NUM-
Columns are returned into the array having an enumerated index.
MYSQLI_BOTH-
Columns are returned into the array having both a numerical index and the fieldname as the associative index.
MYSQLI_NOT_NULL_FLAG-
Indicates that a field is defined as
NOT NULL MYSQLI_PRI_KEY_FLAG-
Field is part of a primary index
MYSQLI_UNIQUE_KEY_FLAG-
Field is part of a unique index.
MYSQLI_MULTIPLE_KEY_FLAG-
Field is part of an index.
MYSQLI_BLOB_FLAG-
Field is defined as
BLOB MYSQLI_UNSIGNED_FLAG-
Field is defined as
UNSIGNED MYSQLI_ZEROFILL_FLAG-
Field is defined as
ZEROFILL MYSQLI_AUTO_INCREMENT_FLAG-
Field is defined as
AUTO_INCREMENT MYSQLI_TIMESTAMP_FLAG-
Field is defined as
TIMESTAMP MYSQLI_SET_FLAG-
Field is defined as
SET MYSQLI_NUM_FLAG-
Field is defined as
NUMERIC MYSQLI_PART_KEY_FLAG-
Field is part of an multi-index
MYSQLI_GROUP_FLAG-
Field is part of
GROUP BY MYSQLI_TYPE_DECIMAL-
Field is defined as
DECIMAL MYSQLI_TYPE_NEWDECIMAL-
Precision math
DECIMALorNUMERICfield (MySQL 5.0.3 and up) MYSQLI_TYPE_BIT-
Field is defined as
BIT(MySQL 5.0.3 and up) MYSQLI_TYPE_TINY-
Field is defined as
TINYINT MYSQLI_TYPE_SHORT-
Field is defined as
SMALLINT MYSQLI_TYPE_LONG-
Field is defined as
INT MYSQLI_TYPE_FLOAT-
Field is defined as
FLOAT MYSQLI_TYPE_DOUBLE-
Field is defined as
DOUBLE MYSQLI_TYPE_NULL-
Field is defined as
DEFAULT NULL MYSQLI_TYPE_TIMESTAMP-
Field is defined as
TIMESTAMP MYSQLI_TYPE_LONGLONG-
Field is defined as
BIGINT MYSQLI_TYPE_INT24-
Field is defined as
MEDIUMINT MYSQLI_TYPE_DATE-
Field is defined as
DATE MYSQLI_TYPE_TIME-
Field is defined as
TIME MYSQLI_TYPE_DATETIME-
Field is defined as
DATETIME MYSQLI_TYPE_YEAR-
Field is defined as
YEAR MYSQLI_TYPE_NEWDATE-
Field is defined as
DATE MYSQLI_TYPE_INTERVAL-
Field is defined as
INTERVAL MYSQLI_TYPE_ENUM-
Field is defined as
ENUM MYSQLI_TYPE_SET-
Field is defined as
SET MYSQLI_TYPE_TINY_BLOB-
Field is defined as
TINYBLOB MYSQLI_TYPE_MEDIUM_BLOB-
Field is defined as
MEDIUMBLOB MYSQLI_TYPE_LONG_BLOB-
Field is defined as
LONGBLOB MYSQLI_TYPE_BLOB-
Field is defined as
BLOB MYSQLI_TYPE_VAR_STRING-
Field is defined as
VARCHAR MYSQLI_TYPE_STRING-
Field is defined as
CHARorBINARY MYSQLI_TYPE_CHAR-
Field is defined as
TINYINT. ForCHAR, seeMYSQLI_TYPE_STRING MYSQLI_TYPE_GEOMETRY-
Field is defined as
GEOMETRY MYSQLI_NEED_DATA-
More data available for bind variable
MYSQLI_NO_DATA-
No more data available for bind variable
MYSQLI_DATA_TRUNCATED-
Data truncation occurred. Available since PHP 5.1.0 and MySQL 5.0.5.
MYSQLI_ENUM_FLAG-
Field is defined as
ENUM. Available since PHP 5.3.0. MYSQLI_BINARY_FLAG-
Field is defined as
BINARY. Available since PHP 5.3.0. MYSQLI_CURSOR_TYPE_FOR_UPDATE-
MYSQLI_CURSOR_TYPE_NO_CURSOR-
MYSQLI_CURSOR_TYPE_READ_ONLY-
MYSQLI_CURSOR_TYPE_SCROLLABLE-
MYSQLI_STMT_ATTR_CURSOR_TYPE-
MYSQLI_STMT_ATTR_PREFETCH_ROWS-
MYSQLI_STMT_ATTR_UPDATE_MAX_LENGTH-
MYSQLI_SET_CHARSET_NAME-
MYSQLI_REPORT_INDEX-
Report if no index or bad index was used in a query.
MYSQLI_REPORT_ERROR-
Report errors from mysqli function calls.
MYSQLI_REPORT_STRICT-
Throw a
mysqli_sql_exceptionfor errors instead of warnings. MYSQLI_REPORT_ALL-
Set all options on (report all).
MYSQLI_REPORT_OFF-
Turns reporting off.
MYSQLI_DEBUG_TRACE_ENABLED-
Is set to 1 if mysqli_debug() functionality is enabled.
MYSQLI_SERVER_QUERY_NO_GOOD_INDEX_USED-
MYSQLI_SERVER_QUERY_NO_INDEX_USED-
MYSQLI_SERVER_PUBLIC_KEY-
Available since PHP 5.5.0.
MYSQLI_REFRESH_GRANT-
Refreshes the grant tables.
MYSQLI_REFRESH_LOG-
Flushes the logs, like executing the
FLUSH LOGSSQL statement. MYSQLI_REFRESH_TABLES-
Flushes the table cache, like executing the
FLUSH TABLESSQL statement. MYSQLI_REFRESH_HOSTS-
Flushes the host cache, like executing the
FLUSH HOSTSSQL statement. MYSQLI_REFRESH_STATUS-
Reset the status variables, like executing the
FLUSH STATUSSQL statement. MYSQLI_REFRESH_THREADS-
Flushes the thread cache.
MYSQLI_REFRESH_SLAVE-
On a slave replication server: resets the master server information, and restarts the slave. Like executing the
RESET SLAVESQL statement. MYSQLI_REFRESH_MASTER-
On a master replication server: removes the binary log files listed in the binary log index, and truncates the index file. Like executing the
RESET MASTERSQL statement. MYSQLI_TRANS_COR_AND_CHAIN-
Appends "AND CHAIN" to mysqli_commit() or mysqli_rollback().
MYSQLI_TRANS_COR_AND_NO_CHAIN-
Appends "AND NO CHAIN" to mysqli_commit() or mysqli_rollback().
MYSQLI_TRANS_COR_RELEASE-
Appends "RELEASE" to mysqli_commit() or mysqli_rollback().
MYSQLI_TRANS_COR_NO_RELEASE-
Appends "NO RELEASE" to mysqli_commit() or mysqli_rollback().
MYSQLI_TRANS_START_READ_ONLY-
Start the transaction as "START TRANSACTION READ ONLY" with mysqli_begin_transaction().
MYSQLI_TRANS_START_READ_WRITE-
Start the transaction as "START TRANSACTION READ WRITE" with mysqli_begin_transaction().
MYSQLI_TRANS_START_CONSISTENT_SNAPSHOT-
Start the transaction as "START TRANSACTION WITH CONSISTENT SNAPSHOT" with mysqli_begin_transaction().
MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERT-
Available since PHP 5.6.16. (MySQL 5.6.5 and up)
Notes
Some implementation notes:
-
Support was added for
MYSQL_TYPE_GEOMETRYto the MySQLi extension in PHP 5.3. -
Note there are different internal implementations within
libmysqlclientandmysqlndfor handling columns of typeMYSQL_TYPE_GEOMETRY. Generally speaking,mysqlndwill allocate significantly less memory. For example, if there is aPOINTcolumn in a result set,libmysqlclientmay pre-allocate up to 4GB of RAM although less than 50 bytes are needed for holding aPOINTcolumn in memory. Memory allocation is much lower, less than 50 bytes, if usingmysqlnd.
The MySQLi Extension Function Summary
| mysqli Class | |||
|---|---|---|---|
| OOP Interface | Procedural Interface | Alias (Do not use) | Description |
| Properties | |||
| $mysqli::affected_rows | mysqli_affected_rows() | N/A | Gets the number of affected rows in a previous MySQL operation |
| $mysqli::client_info | mysqli_get_client_info() | N/A | Returns the MySQL client version as a string |
| $mysqli::client_version | mysqli_get_client_version() | N/A | Returns MySQL client version info as an integer |
| $mysqli::connect_errno | mysqli_connect_errno() | N/A | Returns the error code from last connect call |
| $mysqli::connect_error | mysqli_connect_error() | N/A | Returns a string description of the last connect error |
| $mysqli::errno | mysqli_errno() | N/A | Returns the error code for the most recent function call |
| $mysqli::error | mysqli_error() | N/A | Returns a string description of the last error |
| $mysqli::field_count | mysqli_field_count() | N/A | Returns the number of columns for the most recent query |
| $mysqli::host_info | mysqli_get_host_info() | N/A | Returns a string representing the type of connection used |
| $mysqli::protocol_version | mysqli_get_proto_info() | N/A | Returns the version of the MySQL protocol used |
| $mysqli::server_info | mysqli_get_server_info() | N/A | Returns the version of the MySQL server |
| $mysqli::server_version | mysqli_get_server_version() | N/A | Returns the version of the MySQL server as an integer |
| $mysqli::info | mysqli_info() | N/A | Retrieves information about the most recently executed query |
| $mysqli::insert_id | mysqli_insert_id() | N/A | Returns the auto generated id used in the last query |
| $mysqli::sqlstate | mysqli_sqlstate() | N/A | Returns the SQLSTATE error from previous MySQL operation |
| $mysqli::warning_count | mysqli_warning_count() | N/A | Returns the number of warnings from the last query for the given link |
| Methods | |||
| mysqli::autocommit() | mysqli_autocommit() | N/A | Turns on or off auto-committing database modifications |
| mysqli::change_user() | mysqli_change_user() | N/A | Changes the user of the specified database connection |
| mysqli::character_set_name(), mysqli::client_encoding | mysqli_character_set_name() | mysqli_client_encoding() | Returns the default character set for the database connection |
| mysqli::close() | mysqli_close() | N/A | Closes a previously opened database connection |
| mysqli::commit() | mysqli_commit() | N/A | Commits the current transaction |
| mysqli::__construct() | mysqli_connect() | N/A | Open a new connection to the MySQL server [Note: static (i.e. class) method] |
| mysqli::debug() | mysqli_debug() | N/A | Performs debugging operations |
| mysqli::dump_debug_info() | mysqli_dump_debug_info() | N/A | Dump debugging information into the log |
| mysqli::get_charset() | mysqli_get_charset() | N/A | Returns a character set object |
| mysqli::get_connection_stats() | mysqli_get_connection_stats() | N/A | Returns client connection statistics. Available only with mysqlnd. |
| mysqli::get_client_info() | mysqli_get_client_info() | N/A | Returns the MySQL client version as a string |
| mysqli::get_client_stats() | mysqli_get_client_stats() | N/A | Returns client per-process statistics. Available only with mysqlnd. |
| mysqli::get_cache_stats() | mysqli_get_cache_stats() | N/A | Returns client Zval cache statistics. Available only with mysqlnd. |
| mysqli::get_server_info() | mysqli_get_server_info() | N/A | Returns a string representing the version of the MySQL server that the MySQLi extension is connected to |
| mysqli::get_warnings() | mysqli_get_warnings() | N/A | NOT DOCUMENTED |
| mysqli::init() | mysqli_init() | N/A | Initializes MySQLi and returns a resource for use with mysqli_real_connect. [Not called on an object, as it returns a $mysqli object.] |
| mysqli::kill() | mysqli_kill() | N/A | Asks the server to kill a MySQL thread |
| mysqli::more_results() | mysqli_more_results() | N/A | Check if there are any more query results from a multi query |
| mysqli::multi_query() | mysqli_multi_query() | N/A | Performs a query on the database |
| mysqli::next_result() | mysqli_next_result() | N/A | Prepare next result from multi_query |
| mysqli::options() | mysqli_options() | mysqli_set_opt() | Set options |
| mysqli::ping() | mysqli_ping() | N/A | Pings a server connection, or tries to reconnect if the connection has gone down |
| mysqli::prepare() | mysqli_prepare() | N/A | Prepare an SQL statement for execution |
| mysqli::query() | mysqli_query() | N/A | Performs a query on the database |
| mysqli::real_connect() | mysqli_real_connect() | N/A | Opens a connection to a mysql server |
| mysqli::real_escape_string(), mysqli::escape_string() | mysqli_real_escape_string() | mysqli_escape_string() | Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection |
| mysqli::real_query() | mysqli_real_query() | N/A | Execute an SQL query |
| mysqli::refresh() | mysqli_refresh() | N/A | Flushes tables or caches, or resets the replication server information |
| mysqli::rollback() | mysqli_rollback() | N/A | Rolls back current transaction |
| mysqli::select_db() | mysqli_select_db() | N/A | Selects the default database for database queries |
| mysqli::set_charset() | mysqli_set_charset() | N/A | Sets the default client character set |
| mysqli::set_local_infile_default() | mysqli_set_local_infile_default() | N/A | Unsets user defined handler for load local infile command |
| mysqli::set_local_infile_handler() | mysqli_set_local_infile_handler() | N/A | Set callback function for LOAD DATA LOCAL INFILE command |
| mysqli::ssl_set() | mysqli_ssl_set() | N/A | Used for establishing secure connections using SSL |
| mysqli::stat() | mysqli_stat() | N/A | Gets the current system status |
| mysqli::stmt_init() | mysqli_stmt_init() | N/A | Initializes a statement and returns an object for use with mysqli_stmt_prepare |
| mysqli::store_result() | mysqli_store_result() | N/A | Transfers a result set from the last query |
| mysqli::thread_id() | mysqli_thread_id() | N/A | Returns the thread ID for the current connection |
| mysqli::thread_safe() | mysqli_thread_safe() | N/A | Returns whether thread safety is given or not |
| mysqli::use_result() | mysqli_use_result() | N/A | Initiate a result set retrieval |
| MySQL_STMT | |||
|---|---|---|---|
| OOP Interface | Procedural Interface | Alias (Do not use) | Description |
| Properties | |||
| $mysqli_stmt::affected_rows | mysqli_stmt_affected_rows() | N/A | Returns the total number of rows changed, deleted, or inserted by the last executed statement |
| $mysqli_stmt::errno | mysqli_stmt_errno() | N/A | Returns the error code for the most recent statement call |
| $mysqli_stmt::error | mysqli_stmt_error() | N/A | Returns a string description for last statement error |
| $mysqli_stmt::field_count | mysqli_stmt_field_count() | N/A | Returns the number of field in the given statement - not documented |
| $mysqli_stmt::insert_id | mysqli_stmt_insert_id() | N/A | Get the ID generated from the previous INSERT operation |
| $mysqli_stmt::num_rows | mysqli_stmt_num_rows() | N/A | Return the number of rows in statements result set |
| $mysqli_stmt::param_count | mysqli_stmt_param_count() | mysqli_param_count() | Returns the number of parameter for the given statement |
| $mysqli_stmt::sqlstate | mysqli_stmt_sqlstate() | N/A | Returns SQLSTATE error from previous statement operation |
| Methods | |||
| mysqli_stmt::attr_get() | mysqli_stmt_attr_get() | N/A | Used to get the current value of a statement attribute |
| mysqli_stmt::attr_set() | mysqli_stmt_attr_set() | N/A | Used to modify the behavior of a prepared statement |
| mysqli_stmt::bind_param() | mysqli_stmt_bind_param() | mysqli_bind_param() | Binds variables to a prepared statement as parameters |
| mysqli_stmt::bind_result() | mysqli_stmt_bind_result() | mysqli_bind_result() | Binds variables to a prepared statement for result storage |
| mysqli_stmt::close() | mysqli_stmt_close() | N/A | Closes a prepared statement |
| mysqli_stmt::data_seek() | mysqli_stmt_data_seek() | N/A | Seeks to an arbitrary row in statement result set |
| mysqli_stmt::execute() | mysqli_stmt_execute() | mysqli_execute() | Executes a prepared Query |
| mysqli_stmt::fetch() | mysqli_stmt_fetch() | mysqli_fetch() | Fetch results from a prepared statement into the bound variables |
| mysqli_stmt::free_result() | mysqli_stmt_free_result() | N/A | Frees stored result memory for the given statement handle |
| mysqli_stmt::get_result() | mysqli_stmt_get_result() | N/A | Gets a result set from a prepared statement. Available only with mysqlnd. |
| mysqli_stmt::get_warnings() | mysqli_stmt_get_warnings() | N/A | NOT DOCUMENTED |
| mysqli_stmt::more_results() | mysqli_stmt_more_results() | N/A | Checks if there are more query results from a multiple query |
| mysqli_stmt::next_result() | mysqli_stmt_next_result() | N/A | Reads the next result from a multiple query |
| mysqli_stmt::num_rows() | mysqli_stmt_num_rows() | N/A | See also property $mysqli_stmt::num_rows |
| mysqli_stmt::prepare() | mysqli_stmt_prepare() | N/A | Prepare an SQL statement for execution |
| mysqli_stmt::reset() | mysqli_stmt_reset() | N/A | Resets a prepared statement |
| mysqli_stmt::result_metadata() | mysqli_stmt_result_metadata() | mysqli_get_metadata() | Returns result set metadata from a prepared statement |
| mysqli_stmt::send_long_data() | mysqli_stmt_send_long_data() | mysqli_send_long_data() | Send data in blocks |
| mysqli_stmt::store_result() | mysqli_stmt_store_result() | N/A | Transfers a result set from a prepared statement |
| mysqli_result | |||
|---|---|---|---|
| OOP Interface | Procedural Interface | Alias (Do not use) | Description |
| Properties | |||
| $mysqli_result::current_field | mysqli_field_tell() | N/A | Get current field offset of a result pointer |
| $mysqli_result::field_count | mysqli_num_fields() | N/A | Get the number of fields in a result |
| $mysqli_result::lengths | mysqli_fetch_lengths() | N/A | Returns the lengths of the columns of the current row in the result set |
| $mysqli_result::num_rows | mysqli_num_rows() | N/A | Gets the number of rows in a result |
| Methods | |||
| mysqli_result::data_seek() | mysqli_data_seek() | N/A | Adjusts the result pointer to an arbitrary row in the result |
| mysqli_result::fetch_all() | mysqli_fetch_all() | N/A | Fetches all result rows and returns the result set as an associative array, a numeric array, or both. Available only with mysqlnd. |
| mysqli_result::fetch_array() | mysqli_fetch_array() | N/A | Fetch a result row as an associative, a numeric array, or both |
| mysqli_result::fetch_assoc() | mysqli_fetch_assoc() | N/A | Fetch a result row as an associative array |
| mysqli_result::fetch_field_direct() | mysqli_fetch_field_direct() | N/A | Fetch meta-data for a single field |
| mysqli_result::fetch_field() | mysqli_fetch_field() | N/A | Returns the next field in the result set |
| mysqli_result::fetch_fields() | mysqli_fetch_fields() | N/A | Returns an array of objects representing the fields in a result set |
| mysqli_result::fetch_object() | mysqli_fetch_object() | N/A | Returns the current row of a result set as an object |
| mysqli_result::fetch_row() | mysqli_fetch_row() | N/A | Get a result row as an enumerated array |
| mysqli_result::field_seek() | mysqli_field_seek() | N/A | Set result pointer to a specified field offset |
| mysqli_result::free(), mysqli_result::close, mysqli_result::free_result | mysqli_free_result() | N/A | Frees the memory associated with a result |
| MySQL_Driver | |||
|---|---|---|---|
| OOP Interface | Procedural Interface | Alias (Do not use) | Description |
| Properties | |||
| N/A | |||
| Methods | |||
| mysqli_driver::embedded_server_end() | mysqli_embedded_server_end() | N/A | NOT DOCUMENTED |
| mysqli_driver::embedded_server_start() | mysqli_embedded_server_start() | N/A | NOT DOCUMENTED |
Note:
Alias functions are provided for backward compatibility purposes only. Do not use them in new projects.
Examples
Table of Contents
MySQLi extension basic examples
This example shows how to connect, execute a query, use basic error handling, print resulting rows, and disconnect from a MySQL database.
This example uses the freely available Sakila database that can be downloaded from » dev.mysql.com, as described here. To get this example to work, (a) install sakila and (b) modify the connection variables (host, your_user, your_pass).
Example #1 MySQLi extension overview example
<?php
// Let's pass in a $_GET variable to our example, in this case
// it's aid for actor_id in our Sakila database. Let's make it
// default to 1, and cast it to an integer as to avoid SQL injection
// and/or related security problems. Handling all of this goes beyond
// the scope of this simple example. Example:
// http://example.org/script.php?aid=42
if (isset($_GET['aid']) && is_numeric($_GET['aid'])) {
$aid = (int) $_GET['aid'];
} else {
$aid = 1;
}
// Connecting to and selecting a MySQL database named sakila
// Hostname: 127.0.0.1, username: your_user, password: your_pass, db: sakila
$mysqli = new mysqli('127.0.0.1', 'your_user', 'your_pass', 'sakila');
// Oh no! A connect_errno exists so the connection attempt failed!
if ($mysqli->connect_errno) {
// The connection failed. What do you want to do?
// You could contact yourself (email?), log the error, show a nice page, etc.
// You do not want to reveal sensitive information
// Let's try this:
echo "Sorry, this website is experiencing problems.";
// Something you should not do on a public site, but this example will show you
// anyways, is print out MySQL error related information -- you might log this
echo "Error: Failed to make a MySQL connection, here is why: \n";
echo "Errno: " . $mysqli->connect_errno . "\n";
echo "Error: " . $mysqli->connect_error . "\n";
// You might want to show them something nice, but we will simply exit
exit;
}
// Perform an SQL query
$sql = "SELECT actor_id, first_name, last_name FROM actor WHERE actor_id = $aid";
if (!$result = $mysqli->query($sql)) {
// Oh no! The query failed.
echo "Sorry, the website is experiencing problems.";
// Again, do not do this on a public site, but we'll show you how
// to get the error information
echo "Error: Our query failed to execute and here is why: \n";
echo "Query: " . $sql . "\n";
echo "Errno: " . $mysqli->errno . "\n";
echo "Error: " . $mysqli->error . "\n";
exit;
}
// Phew, we made it. We know our MySQL connection and query
// succeeded, but do we have a result?
if ($result->num_rows === 0) {
// Oh, no rows! Sometimes that's expected and okay, sometimes
// it is not. You decide. In this case, maybe actor_id was too
// large?
echo "We could not find a match for ID $aid, sorry about that. Please try again.";
exit;
}
// Now, we know only one result will exist in this example so let's
// fetch it into an associated array where the array's keys are the
// table's column names
$actor = $result->fetch_assoc();
echo "Sometimes I see " . $actor['first_name'] . " " . $actor['last_name'] . " on TV.";
// Now, let's fetch five random actors and output their names to a list.
// We'll add less error handling here as you can do that on your own now
$sql = "SELECT actor_id, first_name, last_name FROM actor ORDER BY rand() LIMIT 5";
if (!$result = $mysqli->query($sql)) {
echo "Sorry, the website is experiencing problems.";
exit;
}
// Print our 5 random actors in a list, and link to each actor
echo "<ul>\n";
while ($actor = $result->fetch_assoc()) {
echo "<li><a href='" . $_SERVER['SCRIPT_FILENAME'] . "?aid=" . $actor['actor_id'] . "'>\n";
echo $actor['first_name'] . ' ' . $actor['last_name'];
echo "</a></li>\n";
}
echo "</ul>\n";
// The script will automatically free the result and close the MySQL
// connection when it exits, but let's just do it anyways
$result->free();
$mysqli->close();
?>
The mysqli class
(PHP 5, PHP 7)
Introduction
Represents a connection between PHP and a MySQL database.
Class synopsis
$host = ini_get("mysqli.default_host")
[, string $username = ini_get("mysqli.default_user")
[, string $passwd = ini_get("mysqli.default_pw")
[, string $dbname = ""
[, int $port = ini_get("mysqli.default_port")
[, string $socket = ini_get("mysqli.default_socket")
]]]]]] )$host = ini_get("mysqli.default_host")
[, string $username = ini_get("mysqli.default_user")
[, string $passwd = ini_get("mysqli.default_pw")
[, string $dbname = ""
[, int $port = ini_get("mysqli.default_port")
[, string $socket = ini_get("mysqli.default_socket")
]]]]]] ) : void&$read
, array &$error
, array &$reject
, int $sec
[, int $usec = 0
] ) : int$host
[, string $username
[, string $passwd
[, string $dbname
[, int $port
[, string $socket
[, int $flags
]]]]]]] ) : boolmysqli::$affected_rows
mysqli_affected_rows
(PHP 5, PHP 7)
mysqli::$affected_rows -- mysqli_affected_rows — Gets the number of affected rows in a previous MySQL operation
Description
Object oriented style
Procedural style
Returns the number of rows affected by the last INSERT,
UPDATE, REPLACE or
DELETE query.
For SELECT statements mysqli_affected_rows() works like mysqli_num_rows().
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
An integer greater than zero indicates the number of rows affected or
retrieved.
Zero indicates that no records were updated for an UPDATE statement, no
rows matched the WHERE clause in the query or that no
query has yet been executed. -1 indicates that the query returned an
error.
Note:
If the number of affected rows is greater than the maximum integer value(
PHP_INT_MAX), the number of affected rows will be returned as a string.
Examples
Example #1 $mysqli->affected_rows example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* Insert rows */
$mysqli->query("CREATE TABLE Language SELECT * from CountryLanguage");
printf("Affected rows (INSERT): %d\n", $mysqli->affected_rows);
$mysqli->query("ALTER TABLE Language ADD Status int default 0");
/* update rows */
$mysqli->query("UPDATE Language SET Status=1 WHERE Percentage > 50");
printf("Affected rows (UPDATE): %d\n", $mysqli->affected_rows);
/* delete rows */
$mysqli->query("DELETE FROM Language WHERE Percentage < 50");
printf("Affected rows (DELETE): %d\n", $mysqli->affected_rows);
/* select all rows */
$result = $mysqli->query("SELECT CountryCode FROM Language");
printf("Affected rows (SELECT): %d\n", $mysqli->affected_rows);
$result->close();
/* Delete table Language */
$mysqli->query("DROP TABLE Language");
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
if (!$link) {
printf("Can't connect to localhost. Error: %s\n", mysqli_connect_error());
exit();
}
/* Insert rows */
mysqli_query($link, "CREATE TABLE Language SELECT * from CountryLanguage");
printf("Affected rows (INSERT): %d\n", mysqli_affected_rows($link));
mysqli_query($link, "ALTER TABLE Language ADD Status int default 0");
/* update rows */
mysqli_query($link, "UPDATE Language SET Status=1 WHERE Percentage > 50");
printf("Affected rows (UPDATE): %d\n", mysqli_affected_rows($link));
/* delete rows */
mysqli_query($link, "DELETE FROM Language WHERE Percentage < 50");
printf("Affected rows (DELETE): %d\n", mysqli_affected_rows($link));
/* select all rows */
$result = mysqli_query($link, "SELECT CountryCode FROM Language");
printf("Affected rows (SELECT): %d\n", mysqli_affected_rows($link));
mysqli_free_result($result);
/* Delete table Language */
mysqli_query($link, "DROP TABLE Language");
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Affected rows (INSERT): 984 Affected rows (UPDATE): 168 Affected rows (DELETE): 815 Affected rows (SELECT): 169
See Also
- mysqli_num_rows() - Gets the number of rows in a result
- mysqli_info() - Retrieves information about the most recently executed query
mysqli::autocommit
mysqli_autocommit
(PHP 5, PHP 7)
mysqli::autocommit -- mysqli_autocommit — Turns on or off auto-committing database modifications
Description
Object oriented style
$mode
) : boolProcedural style
Turns on or off auto-commit mode on queries for the database connection.
To determine the current state of autocommit use the SQL command
SELECT @@autocommit.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
mode -
Whether to turn on auto-commit or not.
Return Values
Returns TRUE on success or FALSE on failure.
Notes
Note:
This function doesn't work with non transactional table types (like MyISAM or ISAM).
Examples
Example #1 mysqli::autocommit() example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* turn autocommit on */
$mysqli->autocommit(TRUE);
if ($result = $mysqli->query("SELECT @@autocommit")) {
$row = $result->fetch_row();
printf("Autocommit is %s\n", $row[0]);
$result->free();
}
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
if (!$link) {
printf("Can't connect to localhost. Error: %s\n", mysqli_connect_error());
exit();
}
/* turn autocommit on */
mysqli_autocommit($link, TRUE);
if ($result = mysqli_query($link, "SELECT @@autocommit")) {
$row = mysqli_fetch_row($result);
printf("Autocommit is %s\n", $row[0]);
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Autocommit is 1
See Also
- mysqli_begin_transaction() - Starts a transaction
- mysqli_commit() - Commits the current transaction
- mysqli_rollback() - Rolls back current transaction
mysqli::begin_transaction
mysqli_begin_transaction
(PHP 5 >= 5.5.0, PHP 7)
mysqli::begin_transaction -- mysqli_begin_transaction — Starts a transaction
Description
Object oriented style
$flags = 0
[, string $name
]] ) : boolProcedural style:
Begins a transaction. Requires the InnoDB engine (it is enabled by default). For additional details about how MySQL transactions work, see » http://dev.mysql.com/doc/mysql/en/commit.html.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
flags -
Valid flags are:
-
MYSQLI_TRANS_START_READ_ONLY: Start the transaction as "START TRANSACTION READ ONLY". Requires MySQL 5.6 and above. -
MYSQLI_TRANS_START_READ_WRITE: Start the transaction as "START TRANSACTION READ WRITE". Requires MySQL 5.6 and above. -
MYSQLI_TRANS_START_WITH_CONSISTENT_SNAPSHOT: Start the transaction as "START TRANSACTION WITH CONSISTENT SNAPSHOT".
-
-
name -
Savepoint name for the transaction.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 $mysqli->begin_transaction() example
Object oriented style
<?php
$mysqli = new mysqli("127.0.0.1", "my_user", "my_password", "sakila");
if ($mysqli->connect_errno) {
printf("Connect failed: %s\n", $mysqli->connect_error);
exit();
}
$mysqli->begin_transaction(MYSQLI_TRANS_START_READ_ONLY);
$mysqli->query("SELECT first_name, last_name FROM actor");
$mysqli->commit();
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("127.0.0.1", "my_user", "my_password", "sakila");
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
mysqli_begin_transaction($link, MYSQLI_TRANS_START_READ_ONLY);
mysqli_query($link, "SELECT first_name, last_name FROM actor LIMIT 1");
mysqli_commit($link);
mysqli_close($link);
?>
See Also
- mysqli_autocommit() - Turns on or off auto-committing database modifications
- mysqli_commit() - Commits the current transaction
- mysqli_rollback() - Rolls back current transaction
mysqli::change_user
mysqli_change_user
(PHP 5, PHP 7)
mysqli::change_user -- mysqli_change_user — Changes the user of the specified database connection
Description
Object oriented style
$user
, string $password
, string $database
) : boolProcedural style
Changes the user of the specified database connection and sets the current database.
In order to successfully change users a valid username and
password parameters must be provided and that user must have
sufficient permissions to access the desired database. If for any reason authorization
fails, the current user authentication will remain.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
user -
The MySQL user name.
-
password -
The MySQL password.
-
database -
The database to change to.
If desired, the
NULLvalue may be passed resulting in only changing the user and not selecting a database. To select a database in this case use the mysqli_select_db() function.
Return Values
Returns TRUE on success or FALSE on failure.
Notes
Note:
Using this command will always cause the current database connection to behave as if was a completely new database connection, regardless of if the operation was completed successfully. This reset includes performing a rollback on any active transactions, closing all temporary tables, and unlocking all locked tables.
Examples
Example #1 mysqli::change_user() example
Object oriented style
<?php
/* connect database test */
$mysqli = new mysqli("localhost", "my_user", "my_password", "test");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* Set Variable a */
$mysqli->query("SET @a:=1");
/* reset all and select a new database */
$mysqli->change_user("my_user", "my_password", "world");
if ($result = $mysqli->query("SELECT DATABASE()")) {
$row = $result->fetch_row();
printf("Default database: %s\n", $row[0]);
$result->close();
}
if ($result = $mysqli->query("SELECT @a")) {
$row = $result->fetch_row();
if ($row[0] === NULL) {
printf("Value of variable a is NULL\n");
}
$result->close();
}
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
/* connect database test */
$link = mysqli_connect("localhost", "my_user", "my_password", "test");
/* check connection */
if (!$link) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* Set Variable a */
mysqli_query($link, "SET @a:=1");
/* reset all and select a new database */
mysqli_change_user($link, "my_user", "my_password", "world");
if ($result = mysqli_query($link, "SELECT DATABASE()")) {
$row = mysqli_fetch_row($result);
printf("Default database: %s\n", $row[0]);
mysqli_free_result($result);
}
if ($result = mysqli_query($link, "SELECT @a")) {
$row = mysqli_fetch_row($result);
if ($row[0] === NULL) {
printf("Value of variable a is NULL\n");
}
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Default database: world Value of variable a is NULL
See Also
- mysqli_connect() - Alias of mysqli::__construct
- mysqli_select_db() - Selects the default database for database queries
mysqli::character_set_name
mysqli_character_set_name
(PHP 5, PHP 7)
mysqli::character_set_name -- mysqli_character_set_name — Returns the default character set for the database connection
Description
Object oriented style
Procedural style
Returns the current character set for the database connection.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
The default character set for the current connection
Examples
Example #1 mysqli::character_set_name() example
Object oriented style
<?php
/* Open a connection */
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* Print current character set */
$charset = $mysqli->character_set_name();
printf ("Current character set is %s\n", $charset);
$mysqli->close();
?>
Procedural style
<?php
/* Open a connection */
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (!$link) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* Print current character set */
$charset = mysqli_character_set_name($link);
printf ("Current character set is %s\n",$charset);
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Current character set is latin1_swedish_ci
See Also
- mysqli_set_charset() - Sets the default client character set
- mysqli_client_encoding() - Alias of mysqli_character_set_name
- mysqli_real_escape_string() - Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection
mysqli::close
mysqli_close
(PHP 5, PHP 7)
mysqli::close -- mysqli_close — Closes a previously opened database connection
Description
Object oriented style
Procedural style
Closes a previously opened database connection.
Open non-persistent MySQL connections and result sets are automatically destroyed when a PHP script finishes its execution. So, while explicitly closing open connections and freeing result sets is optional, doing so is recommended. This will immediately return resources to PHP and MySQL, which can improve performance. For related information, see freeing resources
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Returns TRUE on success or FALSE on failure.
Examples
See mysqli_connect().
Notes
Note:
mysqli_close() will not close persistent connections. For additional details, see the manual page on persistent connections.
See Also
- mysqli::__construct() - Open a new connection to the MySQL server
- mysqli_init() - Initializes MySQLi and returns a resource for use with mysqli_real_connect()
- mysqli_real_connect() - Opens a connection to a mysql server
- mysqli_free_result() - Frees the memory associated with a result
mysqli::commit
mysqli_commit
(PHP 5, PHP 7)
mysqli::commit -- mysqli_commit — Commits the current transaction
Description
Object oriented style
$flags = 0
[, string $name
]] ) : boolProcedural style
Commits the current transaction for the database connection.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
flags -
A bitmask of
MYSQLI_TRANS_COR_*constants. -
name -
If provided then
COMMIT/*name*/is executed.
Return Values
Returns TRUE on success or FALSE on failure.
Changelog
| Version | Description |
|---|---|
| 5.5.0 |
Added flags and name
parameters.
|
Examples
Example #1 mysqli::commit() example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$mysqli->query("CREATE TABLE Language LIKE CountryLanguage");
/* set autocommit to off */
$mysqli->autocommit(FALSE);
/* Insert some values */
$mysqli->query("INSERT INTO Language VALUES ('DEU', 'Bavarian', 'F', 11.2)");
$mysqli->query("INSERT INTO Language VALUES ('DEU', 'Swabian', 'F', 9.4)");
/* commit transaction */
if (!$mysqli->commit()) {
print("Transaction commit failed\n");
exit();
}
/* drop table */
$mysqli->query("DROP TABLE Language");
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "test");
/* check connection */
if (!$link) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* set autocommit to off */
mysqli_autocommit($link, FALSE);
mysqli_query($link, "CREATE TABLE Language LIKE CountryLanguage");
/* Insert some values */
mysqli_query($link, "INSERT INTO Language VALUES ('DEU', 'Bavarian', 'F', 11.2)");
mysqli_query($link, "INSERT INTO Language VALUES ('DEU', 'Swabian', 'F', 9.4)");
/* commit transaction */
if (!mysqli_commit($link)) {
print("Transaction commit failed\n");
exit();
}
/* close connection */
mysqli_close($link);
?>
See Also
- mysqli_autocommit() - Turns on or off auto-committing database modifications
- mysqli_begin_transaction() - Starts a transaction
- mysqli_rollback() - Rolls back current transaction
- mysqli_savepoint() - Set a named transaction savepoint
mysqli::$connect_errno
mysqli_connect_errno
(PHP 5, PHP 7)
mysqli::$connect_errno -- mysqli_connect_errno — Returns the error code from last connect call
Description
Object oriented style
Procedural style
Returns the last error code number from the last call to mysqli_connect().
Note:
Client error message numbers are listed in the MySQL errmsg.h header file, server error message numbers are listed in mysqld_error.h. In the MySQL source distribution you can find a complete list of error messages and error numbers in the file Docs/mysqld_error.txt.
Return Values
An error code value for the last call to mysqli_connect(), if it failed. zero means no error occurred.
Examples
Example #1 $mysqli->connect_errno example
Object oriented style
<?php
$mysqli = @new mysqli('localhost', 'fake_user', 'my_password', 'my_db');
if ($mysqli->connect_errno) {
die('Connect Error: ' . $mysqli->connect_errno);
}
?>
Procedural style
<?php
$link = @mysqli_connect('localhost', 'fake_user', 'my_password', 'my_db');
if (!$link) {
die('Connect Error: ' . mysqli_connect_errno());
}
?>
The above examples will output:
Connect Error: 1045
See Also
- mysqli_connect() - Alias of mysqli::__construct
- mysqli_connect_error() - Returns a string description of the last connect error
- mysqli_errno() - Returns the error code for the most recent function call
- mysqli_error() - Returns a string description of the last error
- mysqli_sqlstate() - Returns the SQLSTATE error from previous MySQL operation
mysqli::$connect_error
mysqli_connect_error
(PHP 5, PHP 7)
mysqli::$connect_error -- mysqli_connect_error — Returns a string description of the last connect error
Description
Object oriented style
Procedural style
Returns the last error message string from the last call to mysqli_connect().
Return Values
A string that describes the error. NULL is returned if no error occurred.
Examples
Example #1 $mysqli->connect_error example
Object oriented style
<?php
$mysqli = @new mysqli('localhost', 'fake_user', 'my_password', 'my_db');
// Works as of PHP 5.2.9 and 5.3.0.
if ($mysqli->connect_error) {
die('Connect Error: ' . $mysqli->connect_error);
}
?>
Procedural style
<?php
$link = @mysqli_connect('localhost', 'fake_user', 'my_password', 'my_db');
if (!$link) {
die('Connect Error: ' . mysqli_connect_error());
}
?>
The above examples will output:
Connect Error: Access denied for user 'fake_user'@'localhost' (using password: YES)
Notes
The mysqli->connect_error property only works properly as of PHP versions 5.2.9 and 5.3.0. Use the mysqli_connect_error() function if compatibility with earlier PHP versions is required.
See Also
- mysqli_connect() - Alias of mysqli::__construct
- mysqli_connect_errno() - Returns the error code from last connect call
- mysqli_errno() - Returns the error code for the most recent function call
- mysqli_error() - Returns a string description of the last error
- mysqli_sqlstate() - Returns the SQLSTATE error from previous MySQL operation
mysqli::__construct
mysqli::connect
mysqli_connect
(PHP 5, PHP 7)
mysqli::__construct -- mysqli::connect -- mysqli_connect — Open a new connection to the MySQL server
Description
Object oriented style
$host = ini_get("mysqli.default_host")
[, string $username = ini_get("mysqli.default_user")
[, string $passwd = ini_get("mysqli.default_pw")
[, string $dbname = ""
[, int $port = ini_get("mysqli.default_port")
[, string $socket = ini_get("mysqli.default_socket")
]]]]]] )$host = ini_get("mysqli.default_host")
[, string $username = ini_get("mysqli.default_user")
[, string $passwd = ini_get("mysqli.default_pw")
[, string $dbname = ""
[, int $port = ini_get("mysqli.default_port")
[, string $socket = ini_get("mysqli.default_socket")
]]]]]] ) : voidProcedural style
$host = ini_get("mysqli.default_host")
[, string $username = ini_get("mysqli.default_user")
[, string $passwd = ini_get("mysqli.default_pw")
[, string $dbname = ""
[, int $port = ini_get("mysqli.default_port")
[, string $socket = ini_get("mysqli.default_socket")
]]]]]] ) : mysqliOpens a connection to the MySQL Server.
Parameters
-
host -
Can be either a host name or an IP address. Passing the
NULLvalue or the string "localhost" to this parameter, the local host is assumed. When possible, pipes will be used instead of the TCP/IP protocol.Prepending host by
p:opens a persistent connection. mysqli_change_user() is automatically called on connections opened from the connection pool. -
username -
The MySQL user name.
-
passwd -
If not provided or
NULL, the MySQL server will attempt to authenticate the user against those user records which have no password only. This allows one username to be used with different permissions (depending on if a password is provided or not). -
dbname -
If provided will specify the default database to be used when performing queries.
-
port -
Specifies the port number to attempt to connect to the MySQL server.
-
socket -
Specifies the socket or named pipe that should be used.
Note:
Specifying the
socketparameter will not explicitly determine the type of connection to be used when connecting to the MySQL server. How the connection is made to the MySQL database is determined by thehostparameter.
Return Values
Returns an object which represents the connection to a MySQL Server,
or FALSE on failure.
Changelog
| Version | Description |
|---|---|
| 5.3.0 | Added the ability of persistent connections. |
Examples
Example #1 mysqli::__construct() example
Object oriented style
<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'my_db');
/*
* This is the "official" OO way to do it,
* BUT $connect_error was broken until PHP 5.2.9 and 5.3.0.
*/
if ($mysqli->connect_error) {
die('Connect Error (' . $mysqli->connect_errno . ') '
. $mysqli->connect_error);
}
/*
* Use this instead of $connect_error if you need to ensure
* compatibility with PHP versions prior to 5.2.9 and 5.3.0.
*/
if (mysqli_connect_error()) {
die('Connect Error (' . mysqli_connect_errno() . ') '
. mysqli_connect_error());
}
echo 'Success... ' . $mysqli->host_info . "\n";
$mysqli->close();
?>
Object oriented style when extending mysqli class
<?php
class foo_mysqli extends mysqli {
public function __construct($host, $user, $pass, $db) {
parent::__construct($host, $user, $pass, $db);
if (mysqli_connect_error()) {
die('Connect Error (' . mysqli_connect_errno() . ') '
. mysqli_connect_error());
}
}
}
$db = new foo_mysqli('localhost', 'my_user', 'my_password', 'my_db');
echo 'Success... ' . $db->host_info . "\n";
$db->close();
?>
Procedural style
<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'my_db');
if (!$link) {
die('Connect Error (' . mysqli_connect_errno() . ') '
. mysqli_connect_error());
}
echo 'Success... ' . mysqli_get_host_info($link) . "\n";
mysqli_close($link);
?>
The above examples will output:
Success... MySQL host info: localhost via TCP/IP
Notes
Note:
MySQLnd always assumes the server default charset. This charset is sent during connection hand-shake/authentication, which mysqlnd will use.
Libmysqlclient uses the default charset set in the my.cnf or by an explicit call to mysqli_options() prior to calling mysqli_real_connect(), but after mysqli_init().
Note:
OO syntax only: If a connection fails an object is still returned. To check if the connection failed then use either the mysqli_connect_error() function or the mysqli->connect_error property as in the preceding examples.
Note:
If it is necessary to set options, such as the connection timeout, mysqli_real_connect() must be used instead.
Note:
Calling the constructor with no parameters is the same as calling mysqli_init().
Note:
Error "Can't create TCP/IP socket (10106)" usually means that the variables_order configure directive doesn't contain character
E. On Windows, if the environment is not copied theSYSTEMROOTenvironment variable won't be available and PHP will have problems loading Winsock.
See Also
- mysqli_real_connect() - Opens a connection to a mysql server
- mysqli_options() - Set options
- mysqli_connect_errno() - Returns the error code from last connect call
- mysqli_connect_error() - Returns a string description of the last connect error
- mysqli_close() - Closes a previously opened database connection
mysqli::debug
mysqli_debug
(PHP 5, PHP 7)
mysqli::debug -- mysqli_debug — Performs debugging operations
Description
Object oriented style
$message
) : boolProcedural style
$message
) : boolPerforms debugging operations using the Fred Fish debugging library.
Parameters
-
message -
A string representing the debugging operation to perform
Return Values
Returns TRUE.
Notes
Note:
To use the mysqli_debug() function you must compile the MySQL client library to support debugging.
Examples
Example #1 Generating a Trace File
<?php
/* Create a trace file in '/tmp/client.trace' on the local (client) machine: */
mysqli_debug("d:t:o,/tmp/client.trace");
?>
See Also
- mysqli_dump_debug_info() - Dump debugging information into the log
- mysqli_report() - Alias of mysqli_driver->report_mode
mysqli::dump_debug_info
mysqli_dump_debug_info
(PHP 5, PHP 7)
mysqli::dump_debug_info -- mysqli_dump_debug_info — Dump debugging information into the log
Description
Object oriented style
Procedural style
This function is designed to be executed by an user with the SUPER privilege and is used to dump debugging information into the log for the MySQL Server relating to the connection.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Returns TRUE on success or FALSE on failure.
mysqli::$errno
mysqli_errno
(PHP 5, PHP 7)
mysqli::$errno -- mysqli_errno — Returns the error code for the most recent function call
Description
Object oriented style
Procedural style
Returns the last error code for the most recent MySQLi function call that can succeed or fail.
Client error message numbers are listed in the MySQL errmsg.h header file, server error message numbers are listed in mysqld_error.h. In the MySQL source distribution you can find a complete list of error messages and error numbers in the file Docs/mysqld_error.txt.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
An error code value for the last call, if it failed. zero means no error occurred.
Examples
Example #1 $mysqli->errno example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if ($mysqli->connect_errno) {
printf("Connect failed: %s\n", $mysqli->connect_error);
exit();
}
if (!$mysqli->query("SET a=1")) {
printf("Errorcode: %d\n", $mysqli->errno);
}
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if (!mysqli_query($link, "SET a=1")) {
printf("Errorcode: %d\n", mysqli_errno($link));
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Errorcode: 1193
See Also
- mysqli_connect_errno() - Returns the error code from last connect call
- mysqli_connect_error() - Returns a string description of the last connect error
- mysqli_error() - Returns a string description of the last error
- mysqli_sqlstate() - Returns the SQLSTATE error from previous MySQL operation
mysqli::$error_list
mysqli_error_list
(PHP 5 >= 5.4.0, PHP 7)
mysqli::$error_list -- mysqli_error_list — Returns a list of errors from the last command executed
Description
Object oriented style
Procedural style
Returns a array of errors for the most recent MySQLi function call that can succeed or fail.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
A list of errors, each as an associative array containing the errno, error, and sqlstate.
Examples
Example #1 $mysqli->error_list example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "nobody", "");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if (!$mysqli->query("SET a=1")) {
print_r($mysqli->error_list);
}
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if (!mysqli_query($link, "SET a=1")) {
print_r(mysqli_error_list($link));
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Array
(
[0] => Array
(
[errno] => 1193
[sqlstate] => HY000
[error] => Unknown system variable 'a'
)
)
See Also
- mysqli_connect_errno() - Returns the error code from last connect call
- mysqli_connect_error() - Returns a string description of the last connect error
- mysqli_error() - Returns a string description of the last error
- mysqli_sqlstate() - Returns the SQLSTATE error from previous MySQL operation
mysqli::$error
mysqli_error
(PHP 5, PHP 7)
mysqli::$error -- mysqli_error — Returns a string description of the last error
Description
Object oriented style
Procedural style
Returns the last error message for the most recent MySQLi function call that can succeed or fail.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
A string that describes the error. An empty string if no error occurred.
Examples
Example #1 $mysqli->error example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if ($mysqli->connect_errno) {
printf("Connect failed: %s\n", $mysqli->connect_error);
exit();
}
if (!$mysqli->query("SET a=1")) {
printf("Error message: %s\n", $mysqli->error);
}
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if (!mysqli_query($link, "SET a=1")) {
printf("Error message: %s\n", mysqli_error($link));
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Error message: Unknown system variable 'a'
See Also
- mysqli_connect_errno() - Returns the error code from last connect call
- mysqli_connect_error() - Returns a string description of the last connect error
- mysqli_errno() - Returns the error code for the most recent function call
- mysqli_sqlstate() - Returns the SQLSTATE error from previous MySQL operation
mysqli::$field_count
mysqli_field_count
(PHP 5, PHP 7)
mysqli::$field_count -- mysqli_field_count — Returns the number of columns for the most recent query
Description
Object oriented style
Procedural style
Returns the number of columns for the most recent query on the connection
represented by the link parameter. This function
can be useful when using the mysqli_store_result()
function to determine if the query should have produced a non-empty result
set or not without knowing the nature of the query.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
An integer representing the number of fields in a result set.
Examples
Example #1 $mysqli->field_count example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "test");
$mysqli->query( "DROP TABLE IF EXISTS friends");
$mysqli->query( "CREATE TABLE friends (id int, name varchar(20))");
$mysqli->query( "INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");
$mysqli->real_query("SELECT * FROM friends");
if ($mysqli->field_count) {
/* this was a select/show or describe query */
$result = $mysqli->store_result();
/* process resultset */
$row = $result->fetch_row();
/* free resultset */
$result->close();
}
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "test");
mysqli_query($link, "DROP TABLE IF EXISTS friends");
mysqli_query($link, "CREATE TABLE friends (id int, name varchar(20))");
mysqli_query($link, "INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");
mysqli_real_query($link, "SELECT * FROM friends");
if (mysqli_field_count($link)) {
/* this was a select/show or describe query */
$result = mysqli_store_result($link);
/* process resultset */
$row = mysqli_fetch_row($result);
/* free resultset */
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
mysqli::get_charset
mysqli_get_charset
(PHP 5 >= 5.1.0, PHP 7)
mysqli::get_charset -- mysqli_get_charset — Returns a character set object
Description
Object oriented style
Procedural style
Returns a character set object providing several properties of the current active character set.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
The function returns a character set object with the following properties:
-
charset -
Character set name
-
collation -
Collation name
-
dir -
Directory the charset description was fetched from (?) or "" for built-in character sets
-
min_length -
Minimum character length in bytes
-
max_length -
Maximum character length in bytes
-
number -
Internal character set number
-
state -
Character set status (?)
Examples
Example #1 mysqli::get_charset() example
Object oriented style
<?php
$db = mysqli_init();
$db->real_connect("localhost","root","","test");
var_dump($db->get_charset());
?>
Procedural style
<?php
$db = mysqli_init();
mysqli_real_connect($db, "localhost","root","","test");
var_dump(mysqli_get_charset($db));
?>
The above examples will output:
object(stdClass)#2 (7) {
["charset"]=>
string(6) "latin1"
["collation"]=>
string(17) "latin1_swedish_ci"
["dir"]=>
string(0) ""
["min_length"]=>
int(1)
["max_length"]=>
int(1)
["number"]=>
int(8)
["state"]=>
int(801)
}
See Also
- mysqli_character_set_name() - Returns the default character set for the database connection
- mysqli_set_charset() - Sets the default client character set
mysqli::$client_info
mysqli::get_client_info
mysqli_get_client_info
(PHP 5, PHP 7)
mysqli::$client_info -- mysqli::get_client_info -- mysqli_get_client_info — Get MySQL client info
Description
Object oriented style
Procedural style
Returns a string that represents the MySQL client library version.
Return Values
A string that represents the MySQL client library version
Examples
Example #1 mysqli_get_client_info
<?php
/* We don't need a connection to determine
the version of mysql client library */
printf("Client library version: %s\n", mysqli_get_client_info());
?>
See Also
- mysqli_get_client_version() - Returns the MySQL client version as an integer
- mysqli_get_server_info() - Returns the version of the MySQL server
- mysqli_get_server_version() - Returns the version of the MySQL server as an integer
mysqli::$client_version
mysqli_get_client_version
(PHP 5, PHP 7)
mysqli::$client_version -- mysqli_get_client_version — Returns the MySQL client version as an integer
Description
Object oriented style
Procedural style
Returns client version number as an integer.
Return Values
A number that represents the MySQL client library version in format:
main_version*10000 + minor_version *100 + sub_version.
For example, 4.1.0 is returned as 40100.
This is useful to quickly determine the version of the client library to know if some capability exists.
Examples
Example #1 mysqli_get_client_version
<?php
/* We don't need a connection to determine
the version of mysql client library */
printf("Client library version: %d\n", mysqli_get_client_version());
?>
See Also
- mysqli_get_client_info() - Get MySQL client info
- mysqli_get_server_info() - Returns the version of the MySQL server
- mysqli_get_server_version() - Returns the version of the MySQL server as an integer
mysqli::get_connection_stats
mysqli_get_connection_stats
(PHP 5 >= 5.3.0, PHP 7)
mysqli::get_connection_stats -- mysqli_get_connection_stats — Returns statistics about the client connection
Description
Object oriented style
Procedural style
Returns statistics about the client connection. Available only with mysqlnd.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Returns an array with connection stats if success, FALSE otherwise.
Examples
Example #1 A mysqli_get_connection_stats() example
<?php
$link = mysqli_connect();
print_r(mysqli_get_connection_stats($link));
?>
The above example will output something similar to:
Array
(
[bytes_sent] => 43
[bytes_received] => 80
[packets_sent] => 1
[packets_received] => 2
[protocol_overhead_in] => 8
[protocol_overhead_out] => 4
[bytes_received_ok_packet] => 11
[bytes_received_eof_packet] => 0
[bytes_received_rset_header_packet] => 0
[bytes_received_rset_field_meta_packet] => 0
[bytes_received_rset_row_packet] => 0
[bytes_received_prepare_response_packet] => 0
[bytes_received_change_user_packet] => 0
[packets_sent_command] => 0
[packets_received_ok] => 1
[packets_received_eof] => 0
[packets_received_rset_header] => 0
[packets_received_rset_field_meta] => 0
[packets_received_rset_row] => 0
[packets_received_prepare_response] => 0
[packets_received_change_user] => 0
[result_set_queries] => 0
[non_result_set_queries] => 0
[no_index_used] => 0
[bad_index_used] => 0
[slow_queries] => 0
[buffered_sets] => 0
[unbuffered_sets] => 0
[ps_buffered_sets] => 0
[ps_unbuffered_sets] => 0
[flushed_normal_sets] => 0
[flushed_ps_sets] => 0
[ps_prepared_never_executed] => 0
[ps_prepared_once_executed] => 0
[rows_fetched_from_server_normal] => 0
[rows_fetched_from_server_ps] => 0
[rows_buffered_from_client_normal] => 0
[rows_buffered_from_client_ps] => 0
[rows_fetched_from_client_normal_buffered] => 0
[rows_fetched_from_client_normal_unbuffered] => 0
[rows_fetched_from_client_ps_buffered] => 0
[rows_fetched_from_client_ps_unbuffered] => 0
[rows_fetched_from_client_ps_cursor] => 0
[rows_skipped_normal] => 0
[rows_skipped_ps] => 0
[copy_on_write_saved] => 0
[copy_on_write_performed] => 0
[command_buffer_too_small] => 0
[connect_success] => 1
[connect_failure] => 0
[connection_reused] => 0
[reconnect] => 0
[pconnect_success] => 0
[active_connections] => 1
[active_persistent_connections] => 0
[explicit_close] => 0
[implicit_close] => 0
[disconnect_close] => 0
[in_middle_of_command_close] => 0
[explicit_free_result] => 0
[implicit_free_result] => 0
[explicit_stmt_close] => 0
[implicit_stmt_close] => 0
[mem_emalloc_count] => 0
[mem_emalloc_ammount] => 0
[mem_ecalloc_count] => 0
[mem_ecalloc_ammount] => 0
[mem_erealloc_count] => 0
[mem_erealloc_ammount] => 0
[mem_efree_count] => 0
[mem_malloc_count] => 0
[mem_malloc_ammount] => 0
[mem_calloc_count] => 0
[mem_calloc_ammount] => 0
[mem_realloc_count] => 0
[mem_realloc_ammount] => 0
[mem_free_count] => 0
[proto_text_fetched_null] => 0
[proto_text_fetched_bit] => 0
[proto_text_fetched_tinyint] => 0
[proto_text_fetched_short] => 0
[proto_text_fetched_int24] => 0
[proto_text_fetched_int] => 0
[proto_text_fetched_bigint] => 0
[proto_text_fetched_decimal] => 0
[proto_text_fetched_float] => 0
[proto_text_fetched_double] => 0
[proto_text_fetched_date] => 0
[proto_text_fetched_year] => 0
[proto_text_fetched_time] => 0
[proto_text_fetched_datetime] => 0
[proto_text_fetched_timestamp] => 0
[proto_text_fetched_string] => 0
[proto_text_fetched_blob] => 0
[proto_text_fetched_enum] => 0
[proto_text_fetched_set] => 0
[proto_text_fetched_geometry] => 0
[proto_text_fetched_other] => 0
[proto_binary_fetched_null] => 0
[proto_binary_fetched_bit] => 0
[proto_binary_fetched_tinyint] => 0
[proto_binary_fetched_short] => 0
[proto_binary_fetched_int24] => 0
[proto_binary_fetched_int] => 0
[proto_binary_fetched_bigint] => 0
[proto_binary_fetched_decimal] => 0
[proto_binary_fetched_float] => 0
[proto_binary_fetched_double] => 0
[proto_binary_fetched_date] => 0
[proto_binary_fetched_year] => 0
[proto_binary_fetched_time] => 0
[proto_binary_fetched_datetime] => 0
[proto_binary_fetched_timestamp] => 0
[proto_binary_fetched_string] => 0
[proto_binary_fetched_blob] => 0
[proto_binary_fetched_enum] => 0
[proto_binary_fetched_set] => 0
[proto_binary_fetched_geometry] => 0
[proto_binary_fetched_other] => 0
)
mysqli::$host_info
mysqli_get_host_info
(PHP 5, PHP 7)
mysqli::$host_info -- mysqli_get_host_info — Returns a string representing the type of connection used
Description
Object oriented style
Procedural style
Returns a string describing the connection represented by
the link parameter (including
the server host name).
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
A character string representing the server hostname and the connection type.
Examples
Example #1 $mysqli->host_info example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* print host information */
printf("Host info: %s\n", $mysqli->host_info);
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* print host information */
printf("Host info: %s\n", mysqli_get_host_info($link));
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Host info: Localhost via UNIX socket
mysqli::$protocol_version
mysqli_get_proto_info
(PHP 5, PHP 7)
mysqli::$protocol_version -- mysqli_get_proto_info — Returns the version of the MySQL protocol used
Description
Object oriented style
Procedural style
Returns an integer representing the MySQL protocol version used by the
connection represented by the link parameter.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Returns an integer representing the protocol version.
Examples
Example #1 $mysqli->protocol_version example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* print protocol version */
printf("Protocol version: %d\n", $mysqli->protocol_version);
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* print protocol version */
printf("Protocol version: %d\n", mysqli_get_proto_info($link));
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Protocol version: 10
mysqli::$server_info
mysqli::get_server_info
mysqli_get_server_info
(PHP 5, PHP 7)
mysqli::$server_info -- mysqli::get_server_info -- mysqli_get_server_info — Returns the version of the MySQL server
Description
Object oriented style
Procedural style
Returns a string representing the version of the MySQL server that the MySQLi extension is connected to.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
A character string representing the server version.
Examples
Example #1 $mysqli->server_info example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* print server version */
printf("Server version: %s\n", $mysqli->server_info);
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* print server version */
printf("Server version: %s\n", mysqli_get_server_info($link));
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Server version: 4.1.2-alpha-debug
See Also
- mysqli_get_client_info() - Get MySQL client info
- mysqli_get_client_version() - Returns the MySQL client version as an integer
- mysqli_get_server_version() - Returns the version of the MySQL server as an integer
mysqli::$server_version
mysqli_get_server_version
(PHP 5, PHP 7)
mysqli::$server_version -- mysqli_get_server_version — Returns the version of the MySQL server as an integer
Description
Object oriented style
Procedural style
The mysqli_get_server_version() function returns the
version of the server connected to (represented by the
link parameter) as an integer.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
An integer representing the server version.
The form of this version number is
main_version * 10000 + minor_version * 100 + sub_version
(i.e. version 4.1.0 is 40100).
Examples
Example #1 $mysqli->server_version example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* print server version */
printf("Server version: %d\n", $mysqli->server_version);
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* print server version */
printf("Server version: %d\n", mysqli_get_server_version($link));
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Server version: 40102
See Also
- mysqli_get_client_info() - Get MySQL client info
- mysqli_get_client_version() - Returns the MySQL client version as an integer
- mysqli_get_server_info() - Returns the version of the MySQL server
mysqli::get_warnings
mysqli_get_warnings
(PHP 5 >= 5.1.0, PHP 7)
mysqli::get_warnings -- mysqli_get_warnings — Get result of SHOW WARNINGS
Description
Object oriented style
Procedural style
This function is currently not documented; only its argument list is available.
mysqli::$info
mysqli_info
(PHP 5, PHP 7)
mysqli::$info -- mysqli_info — Retrieves information about the most recently executed query
Description
Object oriented style
Procedural style
The mysqli_info() function returns a string providing information about the last query executed. The nature of this string is provided below:
| Query type | Example result string |
|---|---|
| INSERT INTO...SELECT... | Records: 100 Duplicates: 0 Warnings: 0 |
| INSERT INTO...VALUES (...),(...),(...) | Records: 3 Duplicates: 0 Warnings: 0 |
| LOAD DATA INFILE ... | Records: 1 Deleted: 0 Skipped: 0 Warnings: 0 |
| ALTER TABLE ... | Records: 3 Duplicates: 0 Warnings: 0 |
| UPDATE ... | Rows matched: 40 Changed: 40 Warnings: 0 |
Note:
Queries which do not fall into one of the preceding formats are not supported. In these situations, mysqli_info() will return an empty string.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
A character string representing additional information about the most recently executed query.
Examples
Example #1 $mysqli->info example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$mysqli->query("CREATE TEMPORARY TABLE t1 LIKE City");
/* INSERT INTO .. SELECT */
$mysqli->query("INSERT INTO t1 SELECT * FROM City ORDER BY ID LIMIT 150");
printf("%s\n", $mysqli->info);
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
mysqli_query($link, "CREATE TEMPORARY TABLE t1 LIKE City");
/* INSERT INTO .. SELECT */
mysqli_query($link, "INSERT INTO t1 SELECT * FROM City ORDER BY ID LIMIT 150");
printf("%s\n", mysqli_info($link));
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Records: 150 Duplicates: 0 Warnings: 0
See Also
- mysqli_affected_rows() - Gets the number of affected rows in a previous MySQL operation
- mysqli_warning_count() - Returns the number of warnings from the last query for the given link
- mysqli_num_rows() - Gets the number of rows in a result
mysqli::init
mysqli_init
(PHP 5, PHP 7)
mysqli::init -- mysqli_init — Initializes MySQLi and returns a resource for use with mysqli_real_connect()
Description
Object oriented style
Procedural style
Allocates or initializes a MYSQL object suitable for mysqli_options() and mysqli_real_connect().
Note:
Any subsequent calls to any mysqli function (except mysqli_options()) will fail until mysqli_real_connect() was called.
Return Values
Returns an object.
Examples
See Also
- mysqli_options() - Set options
- mysqli_close() - Closes a previously opened database connection
- mysqli_real_connect() - Opens a connection to a mysql server
- mysqli_connect() - Alias of mysqli::__construct
mysqli::$insert_id
mysqli_insert_id
(PHP 5, PHP 7)
mysqli::$insert_id -- mysqli_insert_id — Returns the auto generated id used in the latest query
Description
Object oriented style
Procedural style
The mysqli_insert_id() function returns the ID generated by a query (usually INSERT) on a table with a column having the AUTO_INCREMENT attribute. If no INSERT or UPDATE statements were sent via this connection, or if the modified table does not have a column with the AUTO_INCREMENT attribute, this function will return zero.
Note:
Performing an INSERT or UPDATE statement using the LAST_INSERT_ID() function will also modify the value returned by the mysqli_insert_id() function.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
The value of the AUTO_INCREMENT field that was updated
by the previous query. Returns zero if there was no previous query on the
connection or if the query did not update an AUTO_INCREMENT
value.
Note:
If the number is greater than maximal int value, mysqli_insert_id() will return a string.
Examples
Example #1 $mysqli->insert_id example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$mysqli->query("CREATE TABLE myCity LIKE City");
$query = "INSERT INTO myCity VALUES (NULL, 'Stuttgart', 'DEU', 'Stuttgart', 617000)";
$mysqli->query($query);
printf ("New Record has id %d.\n", $mysqli->insert_id);
/* drop table */
$mysqli->query("DROP TABLE myCity");
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
mysqli_query($link, "CREATE TABLE myCity LIKE City");
$query = "INSERT INTO myCity VALUES (NULL, 'Stuttgart', 'DEU', 'Stuttgart', 617000)";
mysqli_query($link, $query);
printf ("New Record has id %d.\n", mysqli_insert_id($link));
/* drop table */
mysqli_query($link, "DROP TABLE myCity");
/* close connection */
mysqli_close($link);
?>
The above examples will output:
New Record has id 1.
mysqli::kill
mysqli_kill
(PHP 5, PHP 7)
mysqli::kill -- mysqli_kill — Asks the server to kill a MySQL thread
Description
Object oriented style
$processid
) : boolProcedural style
This function is used to ask the server to kill a MySQL thread specified
by the processid parameter. This value must be
retrieved by calling the mysqli_thread_id() function.
To stop a running query you should use the SQL command
KILL QUERY processid.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 mysqli::kill() example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* determine our thread id */
$thread_id = $mysqli->thread_id;
/* Kill connection */
$mysqli->kill($thread_id);
/* This should produce an error */
if (!$mysqli->query("CREATE TABLE myCity LIKE City")) {
printf("Error: %s\n", $mysqli->error);
exit;
}
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* determine our thread id */
$thread_id = mysqli_thread_id($link);
/* Kill connection */
mysqli_kill($link, $thread_id);
/* This should produce an error */
if (!mysqli_query($link, "CREATE TABLE myCity LIKE City")) {
printf("Error: %s\n", mysqli_error($link));
exit;
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Error: MySQL server has gone away
mysqli::more_results
mysqli_more_results
(PHP 5, PHP 7)
mysqli::more_results -- mysqli_more_results — Check if there are any more query results from a multi query
Description
Object oriented style
Procedural style
Indicates if one or more result sets are available from a previous call to mysqli_multi_query().
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Returns TRUE if one or more result sets (including errors) are available from a previous call to
mysqli_multi_query(), otherwise FALSE.
Examples
See mysqli_multi_query().
See Also
- mysqli_multi_query() - Performs a query on the database
- mysqli_next_result() - Prepare next result from multi_query
- mysqli_store_result() - Transfers a result set from the last query
- mysqli_use_result() - Initiate a result set retrieval
mysqli::multi_query
mysqli_multi_query
(PHP 5, PHP 7)
mysqli::multi_query -- mysqli_multi_query — Performs a query on the database
Description
Object oriented style
$query
) : boolProcedural style
Executes one or multiple queries which are concatenated by a semicolon.
To retrieve the resultset from the first query you can use mysqli_use_result() or mysqli_store_result(). All subsequent query results can be processed using mysqli_more_results() and mysqli_next_result().
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
query -
The query, as a string.
Data inside the query should be properly escaped.
Return Values
Returns FALSE if the first statement failed.
To retrieve subsequent errors from other statements you have to call
mysqli_next_result() first.
Examples
Example #1 mysqli::multi_query() example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT CURRENT_USER();";
$query .= "SELECT Name FROM City ORDER BY ID LIMIT 20, 5";
/* execute multi query */
if ($mysqli->multi_query($query)) {
do {
/* store first result set */
if ($result = $mysqli->store_result()) {
while ($row = $result->fetch_row()) {
printf("%s\n", $row[0]);
}
$result->free();
}
/* print divider */
if ($mysqli->more_results()) {
printf("-----------------\n");
}
} while ($mysqli->next_result());
}
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT CURRENT_USER();";
$query .= "SELECT Name FROM City ORDER BY ID LIMIT 20, 5";
/* execute multi query */
if (mysqli_multi_query($link, $query)) {
do {
/* store first result set */
if ($result = mysqli_store_result($link)) {
while ($row = mysqli_fetch_row($result)) {
printf("%s\n", $row[0]);
}
mysqli_free_result($result);
}
/* print divider */
if (mysqli_more_results($link)) {
printf("-----------------\n");
}
} while (mysqli_next_result($link));
}
/* close connection */
mysqli_close($link);
?>
The above examples will output something similar to:
my_user@localhost ----------------- Amersfoort Maastricht Dordrecht Leiden Haarlemmermeer
See Also
- mysqli_query() - Performs a query on the database
- mysqli_use_result() - Initiate a result set retrieval
- mysqli_store_result() - Transfers a result set from the last query
- mysqli_next_result() - Prepare next result from multi_query
- mysqli_more_results() - Check if there are any more query results from a multi query
mysqli::next_result
mysqli_next_result
(PHP 5, PHP 7)
mysqli::next_result -- mysqli_next_result — Prepare next result from multi_query
Description
Object oriented style
Procedural style
Prepares next result set from a previous call to mysqli_multi_query() which can be retrieved by mysqli_store_result() or mysqli_use_result().
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Returns TRUE on success or FALSE on failure. Also returns FALSE if the next statement resulted in an error, unlike mysqli_more_results().
Examples
See mysqli_multi_query().
See Also
- mysqli_multi_query() - Performs a query on the database
- mysqli_more_results() - Check if there are any more query results from a multi query
- mysqli_store_result() - Transfers a result set from the last query
- mysqli_use_result() - Initiate a result set retrieval
mysqli::options
mysqli_options
(PHP 5, PHP 7)
mysqli::options -- mysqli_options — Set options
Description
Object oriented style
Procedural style
Used to set extra connect options and affect behavior for a connection.
This function may be called multiple times to set several options.
mysqli_options() should be called after mysqli_init() and before mysqli_real_connect().
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
option -
The option that you want to set. It can be one of the following values:
Valid options Name Description MYSQLI_OPT_CONNECT_TIMEOUTconnection timeout in seconds (supported on Windows with TCP/IP since PHP 5.3.1) MYSQLI_OPT_LOCAL_INFILEenable/disable use of LOAD LOCAL INFILEMYSQLI_INIT_COMMANDcommand to execute after when connecting to MySQL server MYSQLI_READ_DEFAULT_FILERead options from named option file instead of my.cnf MYSQLI_READ_DEFAULT_GROUPRead options from the named group from my.cnf or the file specified with MYSQL_READ_DEFAULT_FILE.MYSQLI_SERVER_PUBLIC_KEYRSA public key file used with the SHA-256 based authentication. Available since PHP 5.5.0. MYSQLI_OPT_NET_CMD_BUFFER_SIZEThe size of the internal command/network buffer. Only valid for mysqlnd. Available since PHP 5.3.0. MYSQLI_OPT_NET_READ_BUFFER_SIZEMaximum read chunk size in bytes when reading the body of a MySQL command packet. Only valid for mysqlnd. Available since PHP 5.3.0. MYSQLI_OPT_INT_AND_FLOAT_NATIVEConvert integer and float columns back to PHP numbers. Only valid for mysqlnd. Available since PHP 5.3.0. MYSQLI_OPT_SSL_VERIFY_SERVER_CERTAvailable since PHP 5.3.0. -
value -
The value for the option.
Return Values
Returns TRUE on success or FALSE on failure.
Changelog
| Version | Description |
|---|---|
| 5.5.0 |
The MYSQLI_SERVER_PUBLIC_KEY option was added.
|
| 5.3.0 |
The MYSQLI_OPT_INT_AND_FLOAT_NATIVE,
MYSQLI_OPT_NET_CMD_BUFFER_SIZE,
MYSQLI_OPT_NET_READ_BUFFER_SIZE, and
MYSQLI_OPT_SSL_VERIFY_SERVER_CERT options were
added.
|
Examples
Notes
Note:
MySQLnd always assumes the server default charset. This charset is sent during connection hand-shake/authentication, which mysqlnd will use.
Libmysqlclient uses the default charset set in the my.cnf or by an explicit call to mysqli_options() prior to calling mysqli_real_connect(), but after mysqli_init().
See Also
- mysqli_init() - Initializes MySQLi and returns a resource for use with mysqli_real_connect()
- mysqli_real_connect() - Opens a connection to a mysql server
mysqli::ping
mysqli_ping
(PHP 5, PHP 7)
mysqli::ping -- mysqli_ping — Pings a server connection, or tries to reconnect if the connection has gone down
Description
Object oriented style
Procedural style
Checks whether the connection to the server is working. If it has gone down and global option mysqli.reconnect is enabled, an automatic reconnection is attempted.
Note: The php.ini setting mysqli.reconnect is ignored by the mysqlnd driver, so automatic reconnection is never attempted.
This function can be used by clients that remain idle for a long while, to check whether the server has closed the connection and reconnect if necessary.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 mysqli::ping() example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if ($mysqli->connect_errno) {
printf("Connect failed: %s\n", $mysqli->connect_error);
exit();
}
/* check if server is alive */
if ($mysqli->ping()) {
printf ("Our connection is ok!\n");
} else {
printf ("Error: %s\n", $mysqli->error);
}
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* check if server is alive */
if (mysqli_ping($link)) {
printf ("Our connection is ok!\n");
} else {
printf ("Error: %s\n", mysqli_error($link));
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Our connection is ok!
mysqli::poll
mysqli_poll
(PHP 5 >= 5.3.0, PHP 7)
mysqli::poll -- mysqli_poll — Poll connections
Description
Object oriented style
&$read
, array &$error
, array &$reject
, int $sec
[, int $usec = 0
] ) : intProcedural style
&$read
, array &$error
, array &$reject
, int $sec
[, int $usec = 0
] ) : intPoll connections. Available only with mysqlnd. The method can be used as static.
Parameters
-
read -
List of connections to check for outstanding results that can be read.
-
error -
List of connections on which an error occurred, for example, query failure or lost connection.
-
reject -
List of connections rejected because no asynchronous query has been run on for which the function could poll results.
-
sec -
Maximum number of seconds to wait, must be non-negative.
-
usec -
Maximum number of microseconds to wait, must be non-negative.
Return Values
Returns number of ready connections upon success, FALSE otherwise.
Examples
Example #1 A mysqli_poll() example
<?php
$link1 = mysqli_connect();
$link1->query("SELECT 'test'", MYSQLI_ASYNC);
$all_links = array($link1);
$processed = 0;
do {
$links = $errors = $reject = array();
foreach ($all_links as $link) {
$links[] = $errors[] = $reject[] = $link;
}
if (!mysqli_poll($links, $errors, $reject, 1)) {
continue;
}
foreach ($links as $link) {
if ($result = $link->reap_async_query()) {
print_r($result->fetch_row());
if (is_object($result))
mysqli_free_result($result);
} else die(sprintf("MySQLi Error: %s", mysqli_error($link)));
$processed++;
}
} while ($processed < count($all_links));
?>
The above example will output:
Array
(
[0] => test
)
See Also
- mysqli_query() - Performs a query on the database
- mysqli_reap_async_query() - Get result from async query
mysqli::prepare
mysqli_prepare
(PHP 5, PHP 7)
mysqli::prepare -- mysqli_prepare — Prepare an SQL statement for execution
Description
Object oriented style
Procedural style
Prepares the SQL query, and returns a statement handle to be used for further operations on the statement. The query must consist of a single SQL statement.
The parameter markers must be bound to application variables using mysqli_stmt_bind_param() and/or mysqli_stmt_bind_result() before executing the statement or fetching rows.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
query -
The query, as a string.
Note:
You should not add a terminating semicolon or
\gto the statement.This parameter can include one or more parameter markers in the SQL statement by embedding question mark (
?) characters at the appropriate positions.Note:
The markers are legal only in certain places in SQL statements. For example, they are allowed in the
VALUES()list of anINSERTstatement (to specify column values for a row), or in a comparison with a column in aWHEREclause to specify a comparison value.However, they are not allowed for identifiers (such as table or column names), in the select list that names the columns to be returned by a
SELECTstatement, or to specify both operands of a binary operator such as the=equal sign. The latter restriction is necessary because it would be impossible to determine the parameter type. It's not allowed to compare marker withNULLby? IS NULLtoo. In general, parameters are legal only in Data Manipulation Language (DML) statements, and not in Data Definition Language (DDL) statements.
Return Values
mysqli_prepare() returns a statement object or FALSE if an error occurred.
Examples
Example #1 mysqli::prepare() example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$city = "Amersfoort";
/* create a prepared statement */
if ($stmt = $mysqli->prepare("SELECT District FROM City WHERE Name=?")) {
/* bind parameters for markers */
$stmt->bind_param("s", $city);
/* execute query */
$stmt->execute();
/* bind result variables */
$stmt->bind_result($district);
/* fetch value */
$stmt->fetch();
printf("%s is in district %s\n", $city, $district);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$city = "Amersfoort";
/* create a prepared statement */
if ($stmt = mysqli_prepare($link, "SELECT District FROM City WHERE Name=?")) {
/* bind parameters for markers */
mysqli_stmt_bind_param($stmt, "s", $city);
/* execute query */
mysqli_stmt_execute($stmt);
/* bind result variables */
mysqli_stmt_bind_result($stmt, $district);
/* fetch value */
mysqli_stmt_fetch($stmt);
printf("%s is in district %s\n", $city, $district);
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Amersfoort is in district Utrecht
See Also
- mysqli_stmt_execute() - Executes a prepared Query
- mysqli_stmt_fetch() - Fetch results from a prepared statement into the bound variables
- mysqli_stmt_bind_param() - Binds variables to a prepared statement as parameters
- mysqli_stmt_bind_result() - Binds variables to a prepared statement for result storage
- mysqli_stmt_close() - Closes a prepared statement
mysqli::query
mysqli_query
(PHP 5, PHP 7)
mysqli::query -- mysqli_query — Performs a query on the database
Description
Object oriented style
Procedural style
Performs a query against the database.
For non-DML queries (not INSERT, UPDATE or DELETE), this function is similar to calling mysqli_real_query() followed by either mysqli_use_result() or mysqli_store_result().
Note:
In the case where you pass a statement to mysqli_query() that is longer than
max_allowed_packetof the server, the returned error codes are different depending on whether you are using MySQL Native Driver (mysqlnd) or MySQL Client Library (libmysqlclient). The behavior is as follows:
mysqlndon Linux returns an error code of 1153. The error message meansgot a packet bigger than.max_allowed_packetbytes
mysqlndon Windows returns an error code 2006. This error message meansserver has gone away.
libmysqlclienton all platforms returns an error code 2006. This error message meansserver has gone away.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
query -
The query string.
Data inside the query should be properly escaped.
-
resultmode -
Either the constant
MYSQLI_USE_RESULTorMYSQLI_STORE_RESULTdepending on the desired behavior. By default,MYSQLI_STORE_RESULTis used.If you use
MYSQLI_USE_RESULTall subsequent calls will return errorCommands out of syncunless you call mysqli_free_result()With
MYSQLI_ASYNC(available with mysqlnd), it is possible to perform query asynchronously. mysqli_poll() is then used to get results from such queries.
Return Values
Returns FALSE on failure. For successful SELECT, SHOW, DESCRIBE or
EXPLAIN queries mysqli_query() will return
a mysqli_result object. For other successful queries mysqli_query() will
return TRUE.
Changelog
| Version | Description |
|---|---|
| 5.3.0 | Added the ability of async queries. |
Examples
Example #1 mysqli::query() example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if ($mysqli->connect_errno) {
printf("Connect failed: %s\n", $mysqli->connect_error);
exit();
}
/* Create table doesn't return a resultset */
if ($mysqli->query("CREATE TEMPORARY TABLE myCity LIKE City") === TRUE) {
printf("Table myCity successfully created.\n");
}
/* Select queries return a resultset */
if ($result = $mysqli->query("SELECT Name FROM City LIMIT 10")) {
printf("Select returned %d rows.\n", $result->num_rows);
/* free result set */
$result->close();
}
/* If we have to retrieve large amount of data we use MYSQLI_USE_RESULT */
if ($result = $mysqli->query("SELECT * FROM City", MYSQLI_USE_RESULT)) {
/* Note, that we can't execute any functions which interact with the
server until result set was closed. All calls will return an
'out of sync' error */
if (!$mysqli->query("SET @a:='this will not work'")) {
printf("Error: %s\n", $mysqli->error);
}
$result->close();
}
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* Create table doesn't return a resultset */
if (mysqli_query($link, "CREATE TEMPORARY TABLE myCity LIKE City") === TRUE) {
printf("Table myCity successfully created.\n");
}
/* Select queries return a resultset */
if ($result = mysqli_query($link, "SELECT Name FROM City LIMIT 10")) {
printf("Select returned %d rows.\n", mysqli_num_rows($result));
/* free result set */
mysqli_free_result($result);
}
/* If we have to retrieve large amount of data we use MYSQLI_USE_RESULT */
if ($result = mysqli_query($link, "SELECT * FROM City", MYSQLI_USE_RESULT)) {
/* Note, that we can't execute any functions which interact with the
server until result set was closed. All calls will return an
'out of sync' error */
if (!mysqli_query($link, "SET @a:='this will not work'")) {
printf("Error: %s\n", mysqli_error($link));
}
mysqli_free_result($result);
}
mysqli_close($link);
?>
The above examples will output:
Table myCity successfully created. Select returned 10 rows. Error: Commands out of sync; You can't run this command now
See Also
- mysqli_real_query() - Execute an SQL query
- mysqli_multi_query() - Performs a query on the database
- mysqli_free_result() - Frees the memory associated with a result
mysqli::real_connect
mysqli_real_connect
(PHP 5, PHP 7)
mysqli::real_connect -- mysqli_real_connect — Opens a connection to a mysql server
Description
Object oriented style
$host
[, string $username
[, string $passwd
[, string $dbname
[, int $port
[, string $socket
[, int $flags
]]]]]]] ) : boolProcedural style
$link
[, string $host
[, string $username
[, string $passwd
[, string $dbname
[, int $port
[, string $socket
[, int $flags
]]]]]]] ) : boolEstablish a connection to a MySQL database engine.
This function differs from mysqli_connect():
-
mysqli_real_connect() needs a valid object which has to be created by function mysqli_init().
-
With the mysqli_options() function you can set various options for connection.
-
There is a
flagsparameter.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
host -
Can be either a host name or an IP address. Passing the
NULLvalue or the string "localhost" to this parameter, the local host is assumed. When possible, pipes will be used instead of the TCP/IP protocol. -
username -
The MySQL user name.
-
passwd -
If provided or
NULL, the MySQL server will attempt to authenticate the user against those user records which have no password only. This allows one username to be used with different permissions (depending on if a password as provided or not). -
dbname -
If provided will specify the default database to be used when performing queries.
-
port -
Specifies the port number to attempt to connect to the MySQL server.
-
socket -
Specifies the socket or named pipe that should be used.
Note:
Specifying the
socketparameter will not explicitly determine the type of connection to be used when connecting to the MySQL server. How the connection is made to the MySQL database is determined by thehostparameter. -
flags -
With the parameter
flagsyou can set different connection options:Supported flags Name Description MYSQLI_CLIENT_COMPRESSUse compression protocol MYSQLI_CLIENT_FOUND_ROWSreturn number of matched rows, not the number of affected rows MYSQLI_CLIENT_IGNORE_SPACEAllow spaces after function names. Makes all function names reserved words. MYSQLI_CLIENT_INTERACTIVEAllow interactive_timeoutseconds (instead ofwait_timeoutseconds) of inactivity before closing the connectionMYSQLI_CLIENT_SSLUse SSL (encryption) MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERTLike MYSQLI_CLIENT_SSL, but disables validation of the provided SSL certificate. This is only for installations using MySQL Native Driver and MySQL 5.6 or later.Note:
For security reasons the
MULTI_STATEMENTflag is not supported in PHP. If you want to execute multiple queries use the mysqli_multi_query() function.
Changelog
| Version | Description |
|---|---|
| 5.6.16 |
Added the MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERT flag for MySQL Native Driver
|
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 mysqli::real_connect() example
Object oriented style
<?php
$mysqli = mysqli_init();
if (!$mysqli) {
die('mysqli_init failed');
}
if (!$mysqli->options(MYSQLI_INIT_COMMAND, 'SET AUTOCOMMIT = 0')) {
die('Setting MYSQLI_INIT_COMMAND failed');
}
if (!$mysqli->options(MYSQLI_OPT_CONNECT_TIMEOUT, 5)) {
die('Setting MYSQLI_OPT_CONNECT_TIMEOUT failed');
}
if (!$mysqli->real_connect('localhost', 'my_user', 'my_password', 'my_db')) {
die('Connect Error (' . mysqli_connect_errno() . ') '
. mysqli_connect_error());
}
echo 'Success... ' . $mysqli->host_info . "\n";
$mysqli->close();
?>
Object oriented style when extending mysqli class
<?php
class foo_mysqli extends mysqli {
public function __construct($host, $user, $pass, $db) {
parent::init();
if (!parent::options(MYSQLI_INIT_COMMAND, 'SET AUTOCOMMIT = 0')) {
die('Setting MYSQLI_INIT_COMMAND failed');
}
if (!parent::options(MYSQLI_OPT_CONNECT_TIMEOUT, 5)) {
die('Setting MYSQLI_OPT_CONNECT_TIMEOUT failed');
}
if (!parent::real_connect($host, $user, $pass, $db)) {
die('Connect Error (' . mysqli_connect_errno() . ') '
. mysqli_connect_error());
}
}
}
$db = new foo_mysqli('localhost', 'my_user', 'my_password', 'my_db');
echo 'Success... ' . $db->host_info . "\n";
$db->close();
?>
Procedural style
<?php
$link = mysqli_init();
if (!$link) {
die('mysqli_init failed');
}
if (!mysqli_options($link, MYSQLI_INIT_COMMAND, 'SET AUTOCOMMIT = 0')) {
die('Setting MYSQLI_INIT_COMMAND failed');
}
if (!mysqli_options($link, MYSQLI_OPT_CONNECT_TIMEOUT, 5)) {
die('Setting MYSQLI_OPT_CONNECT_TIMEOUT failed');
}
if (!mysqli_real_connect($link, 'localhost', 'my_user', 'my_password', 'my_db')) {
die('Connect Error (' . mysqli_connect_errno() . ') '
. mysqli_connect_error());
}
echo 'Success... ' . mysqli_get_host_info($link) . "\n";
mysqli_close($link);
?>
The above examples will output:
Success... MySQL host info: localhost via TCP/IP
Notes
Note:
MySQLnd always assumes the server default charset. This charset is sent during connection hand-shake/authentication, which mysqlnd will use.
Libmysqlclient uses the default charset set in the my.cnf or by an explicit call to mysqli_options() prior to calling mysqli_real_connect(), but after mysqli_init().
See Also
- mysqli_connect() - Alias of mysqli::__construct
- mysqli_init() - Initializes MySQLi and returns a resource for use with mysqli_real_connect()
- mysqli_options() - Set options
- mysqli_ssl_set() - Used for establishing secure connections using SSL
- mysqli_close() - Closes a previously opened database connection
mysqli::real_escape_string
mysqli::escape_string
mysqli_real_escape_string
(PHP 5, PHP 7)
mysqli::real_escape_string -- mysqli::escape_string -- mysqli_real_escape_string — Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection
Description
Object oriented style
$escapestr
) : stringProcedural style
This function is used to create a legal SQL string that you can use in an SQL statement. The given string is encoded to an escaped SQL string, taking into account the current character set of the connection.
Security: the default character set
The character set must be set either at the server level, or with the API function mysqli_set_charset() for it to affect mysqli_real_escape_string(). See the concepts section on character sets for more information.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
escapestr -
The string to be escaped.
Characters encoded are
NUL (ASCII 0), \n, \r, \, ', ", and Control-Z.
Return Values
Returns an escaped string.
Errors/Exceptions
Executing this function without a valid MySQLi connection passed in will
return NULL and emit E_WARNING level errors.
Examples
Example #1 mysqli::real_escape_string() example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$mysqli->query("CREATE TEMPORARY TABLE myCity LIKE City");
$city = "'s Hertogenbosch";
/* this query will fail, cause we didn't escape $city */
if (!$mysqli->query("INSERT into myCity (Name) VALUES ('$city')")) {
printf("Error: %s\n", $mysqli->sqlstate);
}
$city = $mysqli->real_escape_string($city);
/* this query with escaped $city will work */
if ($mysqli->query("INSERT into myCity (Name) VALUES ('$city')")) {
printf("%d Row inserted.\n", $mysqli->affected_rows);
}
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
mysqli_query($link, "CREATE TEMPORARY TABLE myCity LIKE City");
$city = "'s Hertogenbosch";
/* this query will fail, cause we didn't escape $city */
if (!mysqli_query($link, "INSERT into myCity (Name) VALUES ('$city')")) {
printf("Error: %s\n", mysqli_sqlstate($link));
}
$city = mysqli_real_escape_string($link, $city);
/* this query with escaped $city will work */
if (mysqli_query($link, "INSERT into myCity (Name) VALUES ('$city')")) {
printf("%d Row inserted.\n", mysqli_affected_rows($link));
}
mysqli_close($link);
?>
The above examples will output:
Error: 42000 1 Row inserted.
Notes
Note:
For those accustomed to using mysql_real_escape_string(), note that the arguments of mysqli_real_escape_string() differ from what mysql_real_escape_string() expects. The
linkidentifier comes first in mysqli_real_escape_string(), whereas the string to be escaped comes first in mysql_real_escape_string().
See Also
- mysqli_set_charset() - Sets the default client character set
- mysqli_character_set_name() - Returns the default character set for the database connection
mysqli::real_query
mysqli_real_query
(PHP 5, PHP 7)
mysqli::real_query -- mysqli_real_query — Execute an SQL query
Description
Object oriented style
$query
) : boolProcedural style
Executes a single query against the database whose result can then be retrieved or stored using the mysqli_store_result() or mysqli_use_result() functions.
In order to determine if a given query should return a result set or not, see mysqli_field_count().
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
query -
The query, as a string.
Data inside the query should be properly escaped.
Return Values
Returns TRUE on success or FALSE on failure.
See Also
- mysqli_query() - Performs a query on the database
- mysqli_store_result() - Transfers a result set from the last query
- mysqli_use_result() - Initiate a result set retrieval
mysqli::reap_async_query
mysqli_reap_async_query
(PHP 5 >= 5.3.0, PHP 7)
mysqli::reap_async_query -- mysqli_reap_async_query — Get result from async query
Description
Object oriented style
Procedural style
Get result from async query. Available only with mysqlnd.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Returns mysqli_result in success, FALSE otherwise.
mysqli::refresh
mysqli_refresh
(PHP 5 >= 5.3.0, PHP 7)
mysqli::refresh -- mysqli_refresh — Refreshes
Description
Object oriented style
$options
) : boolProcedural style
$link
, int $options
) : boolFlushes tables or caches, or resets the replication server information.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
options -
The options to refresh, using the MYSQLI_REFRESH_* constants as documented within the MySQLi constants documentation.
See also the official » MySQL Refresh documentation.
Return Values
TRUE if the refresh was a success, otherwise FALSE
mysqli::release_savepoint
mysqli_release_savepoint
(PHP 5 >= 5.5.0, PHP 7)
mysqli::release_savepoint -- mysqli_release_savepoint — Removes the named savepoint from the set of savepoints of the current transaction
Description
Object oriented style
$name
) : boolProcedural style:
This function is currently not documented; only its argument list is available.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
name -
Return Values
Returns TRUE on success or FALSE on failure.
mysqli::rollback
mysqli_rollback
(PHP 5, PHP 7)
mysqli::rollback -- mysqli_rollback — Rolls back current transaction
Description
Object oriented style
$flags = 0
[, string $name
]] ) : boolProcedural style
Rollbacks the current transaction for the database.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
flags -
A bitmask of
MYSQLI_TRANS_COR_*constants. -
name -
If provided then
ROLLBACK/*name*/is executed.
Return Values
Returns TRUE on success or FALSE on failure.
Changelog
| Version | Description |
|---|---|
| 5.5.0 |
Added flags and name
parameters.
|
Examples
Example #1 mysqli::rollback() example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* disable autocommit */
$mysqli->autocommit(FALSE);
$mysqli->query("CREATE TABLE myCity LIKE City");
$mysqli->query("ALTER TABLE myCity Type=InnoDB");
$mysqli->query("INSERT INTO myCity SELECT * FROM City LIMIT 50");
/* commit insert */
$mysqli->commit();
/* delete all rows */
$mysqli->query("DELETE FROM myCity");
if ($result = $mysqli->query("SELECT COUNT(*) FROM myCity")) {
$row = $result->fetch_row();
printf("%d rows in table myCity.\n", $row[0]);
/* Free result */
$result->close();
}
/* Rollback */
$mysqli->rollback();
if ($result = $mysqli->query("SELECT COUNT(*) FROM myCity")) {
$row = $result->fetch_row();
printf("%d rows in table myCity (after rollback).\n", $row[0]);
/* Free result */
$result->close();
}
/* Drop table myCity */
$mysqli->query("DROP TABLE myCity");
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* disable autocommit */
mysqli_autocommit($link, FALSE);
mysqli_query($link, "CREATE TABLE myCity LIKE City");
mysqli_query($link, "ALTER TABLE myCity Type=InnoDB");
mysqli_query($link, "INSERT INTO myCity SELECT * FROM City LIMIT 50");
/* commit insert */
mysqli_commit($link);
/* delete all rows */
mysqli_query($link, "DELETE FROM myCity");
if ($result = mysqli_query($link, "SELECT COUNT(*) FROM myCity")) {
$row = mysqli_fetch_row($result);
printf("%d rows in table myCity.\n", $row[0]);
/* Free result */
mysqli_free_result($result);
}
/* Rollback */
mysqli_rollback($link);
if ($result = mysqli_query($link, "SELECT COUNT(*) FROM myCity")) {
$row = mysqli_fetch_row($result);
printf("%d rows in table myCity (after rollback).\n", $row[0]);
/* Free result */
mysqli_free_result($result);
}
/* Drop table myCity */
mysqli_query($link, "DROP TABLE myCity");
mysqli_close($link);
?>
The above examples will output:
0 rows in table myCity. 50 rows in table myCity (after rollback).
See Also
- mysqli_begin_transaction() - Starts a transaction
- mysqli_commit() - Commits the current transaction
- mysqli_autocommit() - Turns on or off auto-committing database modifications
- mysqli_release_savepoint() - Removes the named savepoint from the set of savepoints of the current transaction
mysqli::rpl_query_type
mysqli_rpl_query_type
(PHP 5, PHP 7)
mysqli::rpl_query_type -- mysqli_rpl_query_type — Returns RPL query type
Description
Object oriented style
$query
) : intProcedural style
Returns MYSQLI_RPL_MASTER,
MYSQLI_RPL_SLAVE or
MYSQLI_RPL_ADMIN depending on a query type.
INSERT, UPDATE and similar are
master queries, SELECT is
slave, and FLUSH,
REPAIR and similar are admin.
This function is currently not documented; only its argument list is available.
This function has been DEPRECATED and REMOVED as of PHP 5.3.0.
mysqli::savepoint
mysqli_savepoint
(PHP 5 >= 5.5.0, PHP 7)
mysqli::savepoint -- mysqli_savepoint — Set a named transaction savepoint
Description
Object oriented style
$name
) : boolProcedural style:
This function is currently not documented; only its argument list is available.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
name -
Return Values
Returns TRUE on success or FALSE on failure.
mysqli::select_db
mysqli_select_db
(PHP 5, PHP 7)
mysqli::select_db -- mysqli_select_db — Selects the default database for database queries
Description
Object oriented style
$dbname
) : boolProcedural style
Selects the default database to be used when performing queries against the database connection.
Note:
This function should only be used to change the default database for the connection. You can select the default database with 4th parameter in mysqli_connect().
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
dbname -
The database name.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 mysqli::select_db() example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "test");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* return name of current default database */
if ($result = $mysqli->query("SELECT DATABASE()")) {
$row = $result->fetch_row();
printf("Default database is %s.\n", $row[0]);
$result->close();
}
/* change db to world db */
$mysqli->select_db("world");
/* return name of current default database */
if ($result = $mysqli->query("SELECT DATABASE()")) {
$row = $result->fetch_row();
printf("Default database is %s.\n", $row[0]);
$result->close();
}
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "test");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* return name of current default database */
if ($result = mysqli_query($link, "SELECT DATABASE()")) {
$row = mysqli_fetch_row($result);
printf("Default database is %s.\n", $row[0]);
mysqli_free_result($result);
}
/* change db to world db */
mysqli_select_db($link, "world");
/* return name of current default database */
if ($result = mysqli_query($link, "SELECT DATABASE()")) {
$row = mysqli_fetch_row($result);
printf("Default database is %s.\n", $row[0]);
mysqli_free_result($result);
}
mysqli_close($link);
?>
The above examples will output:
Default database is test. Default database is world.
See Also
- mysqli_connect() - Alias of mysqli::__construct
- mysqli_real_connect() - Opens a connection to a mysql server
mysqli::send_query
mysqli_send_query
(PHP 5, PHP 7)
mysqli::send_query -- mysqli_send_query — Send the query and return
Description
Object oriented style
$query
) : boolProcedural style
This function is currently not documented; only its argument list is available.
This function has been DEPRECATED and REMOVED as of PHP 5.3.0.
mysqli::set_charset
mysqli_set_charset
(PHP 5 >= 5.0.5, PHP 7)
mysqli::set_charset -- mysqli_set_charset — Sets the default client character set
Description
Object oriented style
$charset
) : boolProcedural style
Sets the default character set to be used when sending data from and to the database server.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
charset -
The charset to be set as default.
Return Values
Returns TRUE on success or FALSE on failure.
Notes
Note:
To use this function on a Windows platform you need MySQL client library version 4.1.11 or above (for MySQL 5.0 you need 5.0.6 or above).
Note:
This is the preferred way to change the charset. Using mysqli_query() to set it (such as
SET NAMES utf8) is not recommended. See the MySQL character set concepts section for more information.
Examples
Example #1 mysqli::set_charset() example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "test");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
printf("Initial character set: %s\n", $mysqli->character_set_name());
/* change character set to utf8 */
if (!$mysqli->set_charset("utf8")) {
printf("Error loading character set utf8: %s\n", $mysqli->error);
exit();
} else {
printf("Current character set: %s\n", $mysqli->character_set_name());
}
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'test');
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
printf("Initial character set: %s\n", mysqli_character_set_name($link));
/* change character set to utf8 */
if (!mysqli_set_charset($link, "utf8")) {
printf("Error loading character set utf8: %s\n", mysqli_error($link));
exit();
} else {
printf("Current character set: %s\n", mysqli_character_set_name($link));
}
mysqli_close($link);
?>
The above examples will output something similar to:
Initial character set: latin1 Current character set: utf8
See Also
- mysqli_character_set_name() - Returns the default character set for the database connection
- mysqli_real_escape_string() - Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection
- MySQL character set concepts
- » List of character sets that MySQL supports
mysqli::set_local_infile_default
mysqli_set_local_infile_default
(PHP 5 < 5.4.0)
mysqli::set_local_infile_default -- mysqli_set_local_infile_default — Unsets user defined handler for load local infile command
Description
Object oriented style
Procedural style
Deactivates a LOAD DATA INFILE LOCAL handler previously
set with mysqli_set_local_infile_handler().
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
No value is returned.
Examples
See mysqli_set_local_infile_handler() examples
See Also
- mysqli_set_local_infile_handler() - Set callback function for LOAD DATA LOCAL INFILE command
mysqli::set_local_infile_handler
mysqli_set_local_infile_handler
(PHP 5, PHP 7)
mysqli::set_local_infile_handler -- mysqli_set_local_infile_handler — Set callback function for LOAD DATA LOCAL INFILE command
Description
Object oriented style
Procedural style
Set callback function for LOAD DATA LOCAL INFILE command
The callbacks task is to read input from the file specified in the
LOAD DATA LOCAL INFILE and to reformat it into
the format understood by LOAD DATA INFILE.
The returned data needs to match the format specified in the
LOAD DATA
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
read_func -
A callback function or object method taking the following parameters:
-
stream -
A PHP stream associated with the SQL commands INFILE
-
&buffer -
A string buffer to store the rewritten input into
-
buflen -
The maximum number of characters to be stored in the buffer
-
&errormsg -
If an error occurs you can store an error message in here
-
The callback function should return the number of characters stored
in the buffer or a negative value if an error
occurred.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 mysqli::set_local_infile_handler() example
Object oriented style
<?php
$db = mysqli_init();
$db->real_connect("localhost","root","","test");
function callme($stream, &$buffer, $buflen, &$errmsg)
{
$buffer = fgets($stream);
echo $buffer;
// convert to upper case and replace "," delimiter with [TAB]
$buffer = strtoupper(str_replace(",", "\t", $buffer));
return strlen($buffer);
}
echo "Input:\n";
$db->set_local_infile_handler("callme");
$db->query("LOAD DATA LOCAL INFILE 'input.txt' INTO TABLE t1");
$db->set_local_infile_default();
$res = $db->query("SELECT * FROM t1");
echo "\nResult:\n";
while ($row = $res->fetch_assoc()) {
echo join(",", $row)."\n";
}
?>
Procedural style
<?php
$db = mysqli_init();
mysqli_real_connect($db, "localhost","root","","test");
function callme($stream, &$buffer, $buflen, &$errmsg)
{
$buffer = fgets($stream);
echo $buffer;
// convert to upper case and replace "," delimiter with [TAB]
$buffer = strtoupper(str_replace(",", "\t", $buffer));
return strlen($buffer);
}
echo "Input:\n";
mysqli_set_local_infile_handler($db, "callme");
mysqli_query($db, "LOAD DATA LOCAL INFILE 'input.txt' INTO TABLE t1");
mysqli_set_local_infile_default($db);
$res = mysqli_query($db, "SELECT * FROM t1");
echo "\nResult:\n";
while ($row = mysqli_fetch_assoc($res)) {
echo join(",", $row)."\n";
}
?>
The above examples will output:
Input: 23,foo 42,bar Output: 23,FOO 42,BAR
See Also
- mysqli_set_local_infile_default() - Unsets user defined handler for load local infile command
mysqli::$sqlstate
mysqli_sqlstate
(PHP 5, PHP 7)
mysqli::$sqlstate -- mysqli_sqlstate — Returns the SQLSTATE error from previous MySQL operation
Description
Object oriented style
Procedural style
Returns a string containing the SQLSTATE error code for the last error.
The error code consists of five characters. '00000' means no error.
The values are specified by ANSI SQL and ODBC. For a list of possible values, see
» http://dev.mysql.com/doc/mysql/en/error-handling.html.
Note:
Note that not all MySQL errors are yet mapped to SQLSTATE's. The value
HY000(general error) is used for unmapped errors.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Returns a string containing the SQLSTATE error code for the last error.
The error code consists of five characters. '00000' means no error.
Examples
Example #1 $mysqli->sqlstate example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* Table City already exists, so we should get an error */
if (!$mysqli->query("CREATE TABLE City (ID INT, Name VARCHAR(30))")) {
printf("Error - SQLSTATE %s.\n", $mysqli->sqlstate);
}
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* Table City already exists, so we should get an error */
if (!mysqli_query($link, "CREATE TABLE City (ID INT, Name VARCHAR(30))")) {
printf("Error - SQLSTATE %s.\n", mysqli_sqlstate($link));
}
mysqli_close($link);
?>
The above examples will output:
Error - SQLSTATE 42S01.
See Also
- mysqli_errno() - Returns the error code for the most recent function call
- mysqli_error() - Returns a string description of the last error
mysqli::ssl_set
mysqli_ssl_set
(PHP 5, PHP 7)
mysqli::ssl_set -- mysqli_ssl_set — Used for establishing secure connections using SSL
Description
Object oriented style
$key
, string $cert
, string $ca
, string $capath
, string $cipher
) : boolProcedural style
$link
, string $key
, string $cert
, string $ca
, string $capath
, string $cipher
) : boolUsed for establishing secure connections using SSL. It must be called before mysqli_real_connect(). This function does nothing unless OpenSSL support is enabled.
Note that MySQL Native Driver does not support SSL before PHP 5.3.3, so calling this function when using MySQL Native Driver will result in an error. MySQL Native Driver is enabled by default on Microsoft Windows from PHP version 5.3 onwards.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
key -
The path name to the key file.
-
cert -
The path name to the certificate file.
-
ca -
The path name to the certificate authority file.
-
capath -
The pathname to a directory that contains trusted SSL CA certificates in PEM format.
-
cipher -
A list of allowable ciphers to use for SSL encryption.
Return Values
This function always returns TRUE value. If SSL setup is
incorrect mysqli_real_connect() will return an error
when you attempt to connect.
See Also
- mysqli_options() - Set options
- mysqli_real_connect() - Opens a connection to a mysql server
mysqli::stat
mysqli_stat
(PHP 5, PHP 7)
mysqli::stat -- mysqli_stat — Gets the current system status
Description
Object oriented style
Procedural style
mysqli_stat() returns a string containing information similar to that provided by the 'mysqladmin status' command. This includes uptime in seconds and the number of running threads, questions, reloads, and open tables.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
A string describing the server status. FALSE if an error occurred.
Examples
Example #1 mysqli::stat() example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
printf ("System status: %s\n", $mysqli->stat());
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
printf("System status: %s\n", mysqli_stat($link));
mysqli_close($link);
?>
The above examples will output:
System status: Uptime: 272 Threads: 1 Questions: 5340 Slow queries: 0 Opens: 13 Flush tables: 1 Open tables: 0 Queries per second avg: 19.632 Memory in use: 8496K Max memory used: 8560K
mysqli::stmt_init
mysqli_stmt_init
(PHP 5, PHP 7)
mysqli::stmt_init -- mysqli_stmt_init — Initializes a statement and returns an object for use with mysqli_stmt_prepare
Description
Object oriented style
Procedural style
Allocates and initializes a statement object suitable for mysqli_stmt_prepare().
Note:
Any subsequent calls to any mysqli_stmt function will fail until mysqli_stmt_prepare() was called.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Returns an object.
mysqli::store_result
mysqli_store_result
(PHP 5, PHP 7)
mysqli::store_result -- mysqli_store_result — Transfers a result set from the last query
Description
Object oriented style
Procedural style
Transfers the result set from the last query on the database connection
represented by the link parameter to be used with
the mysqli_data_seek() function.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
option -
The option that you want to set. It can be one of the following values:
Valid options Name Description MYSQLI_STORE_RESULT_COPY_DATACopy results from the internal mysqlnd buffer into the PHP variables fetched. By default, mysqlnd will use a reference logic to avoid copying and duplicating results held in memory. For certain result sets, for example, result sets with many small rows, the copy approach can reduce the overall memory usage because PHP variables holding results may be released earlier (available with mysqlnd only, since PHP 5.6.0)
Return Values
Returns a buffered result object or FALSE if an error occurred.
Note:
mysqli_store_result() returns
FALSEin case the query didn't return a result set (if the query was, for example an INSERT statement). This function also returnsFALSEif the reading of the result set failed. You can check if you have got an error by checking if mysqli_error() doesn't return an empty string, if mysqli_errno() returns a non zero value, or if mysqli_field_count() returns a non zero value. Also possible reason for this function returningFALSEafter successful call to mysqli_query() can be too large result set (memory for it cannot be allocated). If mysqli_field_count() returns a non-zero value, the statement should have produced a non-empty result set.
Notes
Note:
Although it is always good practice to free the memory used by the result of a query using the mysqli_free_result() function, when transferring large result sets using the mysqli_store_result() this becomes particularly important.
Examples
See mysqli_multi_query().
See Also
- mysqli_real_query() - Execute an SQL query
- mysqli_use_result() - Initiate a result set retrieval
mysqli::$thread_id
mysqli_thread_id
(PHP 5, PHP 7)
mysqli::$thread_id -- mysqli_thread_id — Returns the thread ID for the current connection
Description
Object oriented style
Procedural style
The mysqli_thread_id() function returns the thread ID for the current connection which can then be killed using the mysqli_kill() function. If the connection is lost and you reconnect with mysqli_ping(), the thread ID will be other. Therefore you should get the thread ID only when you need it.
Note:
The thread ID is assigned on a connection-by-connection basis. Hence, if the connection is broken and then re-established a new thread ID will be assigned.
To kill a running query you can use the SQL command
KILL QUERY processid.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Returns the Thread ID for the current connection.
Examples
Example #1 $mysqli->thread_id example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* determine our thread id */
$thread_id = $mysqli->thread_id;
/* Kill connection */
$mysqli->kill($thread_id);
/* This should produce an error */
if (!$mysqli->query("CREATE TABLE myCity LIKE City")) {
printf("Error: %s\n", $mysqli->error);
exit;
}
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* determine our thread id */
$thread_id = mysqli_thread_id($link);
/* Kill connection */
mysqli_kill($link, $thread_id);
/* This should produce an error */
if (!mysqli_query($link, "CREATE TABLE myCity LIKE City")) {
printf("Error: %s\n", mysqli_error($link));
exit;
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Error: MySQL server has gone away
mysqli::thread_safe
mysqli_thread_safe
(PHP 5, PHP 7)
mysqli::thread_safe -- mysqli_thread_safe — Returns whether thread safety is given or not
Description
Object oriented style
Procedural style
Tells whether the client library is compiled as thread-safe.
Return Values
TRUE if the client library is thread-safe, otherwise FALSE.
mysqli::use_result
mysqli_use_result
(PHP 5, PHP 7)
mysqli::use_result -- mysqli_use_result — Initiate a result set retrieval
Description
Object oriented style
Procedural style
Used to initiate the retrieval of a result set from the last query executed using the mysqli_real_query() function on the database connection.
Either this or the mysqli_store_result() function must be called before the results of a query can be retrieved, and one or the other must be called to prevent the next query on that database connection from failing.
Note:
The mysqli_use_result() function does not transfer the entire result set from the database and hence cannot be used functions such as mysqli_data_seek() to move to a particular row within the set. To use this functionality, the result set must be stored using mysqli_store_result(). One should not use mysqli_use_result() if a lot of processing on the client side is performed, since this will tie up the server and prevent other threads from updating any tables from which the data is being fetched.
Return Values
Returns an unbuffered result object or FALSE if an error occurred.
Examples
Example #1 mysqli::use_result() example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT CURRENT_USER();";
$query .= "SELECT Name FROM City ORDER BY ID LIMIT 20, 5";
/* execute multi query */
if ($mysqli->multi_query($query)) {
do {
/* store first result set */
if ($result = $mysqli->use_result()) {
while ($row = $result->fetch_row()) {
printf("%s\n", $row[0]);
}
$result->close();
}
/* print divider */
if ($mysqli->more_results()) {
printf("-----------------\n");
}
} while ($mysqli->next_result());
}
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT CURRENT_USER();";
$query .= "SELECT Name FROM City ORDER BY ID LIMIT 20, 5";
/* execute multi query */
if (mysqli_multi_query($link, $query)) {
do {
/* store first result set */
if ($result = mysqli_use_result($link)) {
while ($row = mysqli_fetch_row($result)) {
printf("%s\n", $row[0]);
}
mysqli_free_result($result);
}
/* print divider */
if (mysqli_more_results($link)) {
printf("-----------------\n");
}
} while (mysqli_next_result($link));
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
my_user@localhost ----------------- Amersfoort Maastricht Dordrecht Leiden Haarlemmermeer
See Also
- mysqli_real_query() - Execute an SQL query
- mysqli_store_result() - Transfers a result set from the last query
mysqli::$warning_count
mysqli_warning_count
(PHP 5, PHP 7)
mysqli::$warning_count -- mysqli_warning_count — Returns the number of warnings from the last query for the given link
Description
Object oriented style
Procedural style
Returns the number of warnings from the last query in the connection.
Note:
For retrieving warning messages you can use the SQL command
SHOW WARNINGS [limit row_count].
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Number of warnings or zero if there are no warnings.
Examples
Example #1 $mysqli->warning_count example
Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$mysqli->query("CREATE TABLE myCity LIKE City");
/* a remarkable city in Wales */
$query = "INSERT INTO myCity (CountryCode, Name) VALUES('GBR',
'Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch')";
$mysqli->query($query);
if ($mysqli->warning_count) {
if ($result = $mysqli->query("SHOW WARNINGS")) {
$row = $result->fetch_row();
printf("%s (%d): %s\n", $row[0], $row[1], $row[2]);
$result->close();
}
}
/* close connection */
$mysqli->close();
?>
Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
mysqli_query($link, "CREATE TABLE myCity LIKE City");
/* a remarkable long city name in Wales */
$query = "INSERT INTO myCity (CountryCode, Name) VALUES('GBR',
'Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch')";
mysqli_query($link, $query);
if (mysqli_warning_count($link)) {
if ($result = mysqli_query($link, "SHOW WARNINGS")) {
$row = mysqli_fetch_row($result);
printf("%s (%d): %s\n", $row[0], $row[1], $row[2]);
mysqli_free_result($result);
}
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Warning (1264): Data truncated for column 'Name' at row 1
See Also
- mysqli_errno() - Returns the error code for the most recent function call
- mysqli_error() - Returns a string description of the last error
- mysqli_sqlstate() - Returns the SQLSTATE error from previous MySQL operation
Table of Contents
- mysqli::$affected_rows — Gets the number of affected rows in a previous MySQL operation
- mysqli::autocommit — Turns on or off auto-committing database modifications
- mysqli::begin_transaction — Starts a transaction
- mysqli::change_user — Changes the user of the specified database connection
- mysqli::character_set_name — Returns the default character set for the database connection
- mysqli::close — Closes a previously opened database connection
- mysqli::commit — Commits the current transaction
- mysqli::$connect_errno — Returns the error code from last connect call
- mysqli::$connect_error — Returns a string description of the last connect error
- mysqli::__construct — Open a new connection to the MySQL server
- mysqli::debug — Performs debugging operations
- mysqli::dump_debug_info — Dump debugging information into the log
- mysqli::$errno — Returns the error code for the most recent function call
- mysqli::$error_list — Returns a list of errors from the last command executed
- mysqli::$error — Returns a string description of the last error
- mysqli::$field_count — Returns the number of columns for the most recent query
- mysqli::get_charset — Returns a character set object
- mysqli::$client_info — Get MySQL client info
- mysqli::$client_version — Returns the MySQL client version as an integer
- mysqli::get_connection_stats — Returns statistics about the client connection
- mysqli::$host_info — Returns a string representing the type of connection used
- mysqli::$protocol_version — Returns the version of the MySQL protocol used
- mysqli::$server_info — Returns the version of the MySQL server
- mysqli::$server_version — Returns the version of the MySQL server as an integer
- mysqli::get_warnings — Get result of SHOW WARNINGS
- mysqli::$info — Retrieves information about the most recently executed query
- mysqli::init — Initializes MySQLi and returns a resource for use with mysqli_real_connect()
- mysqli::$insert_id — Returns the auto generated id used in the latest query
- mysqli::kill — Asks the server to kill a MySQL thread
- mysqli::more_results — Check if there are any more query results from a multi query
- mysqli::multi_query — Performs a query on the database
- mysqli::next_result — Prepare next result from multi_query
- mysqli::options — Set options
- mysqli::ping — Pings a server connection, or tries to reconnect if the connection has gone down
- mysqli::poll — Poll connections
- mysqli::prepare — Prepare an SQL statement for execution
- mysqli::query — Performs a query on the database
- mysqli::real_connect — Opens a connection to a mysql server
- mysqli::real_escape_string — Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection
- mysqli::real_query — Execute an SQL query
- mysqli::reap_async_query — Get result from async query
- mysqli::refresh — Refreshes
- mysqli::release_savepoint — Removes the named savepoint from the set of savepoints of the current transaction
- mysqli::rollback — Rolls back current transaction
- mysqli::rpl_query_type — Returns RPL query type
- mysqli::savepoint — Set a named transaction savepoint
- mysqli::select_db — Selects the default database for database queries
- mysqli::send_query — Send the query and return
- mysqli::set_charset — Sets the default client character set
- mysqli::set_local_infile_default — Unsets user defined handler for load local infile command
- mysqli::set_local_infile_handler — Set callback function for LOAD DATA LOCAL INFILE command
- mysqli::$sqlstate — Returns the SQLSTATE error from previous MySQL operation
- mysqli::ssl_set — Used for establishing secure connections using SSL
- mysqli::stat — Gets the current system status
- mysqli::stmt_init — Initializes a statement and returns an object for use with mysqli_stmt_prepare
- mysqli::store_result — Transfers a result set from the last query
- mysqli::$thread_id — Returns the thread ID for the current connection
- mysqli::thread_safe — Returns whether thread safety is given or not
- mysqli::use_result — Initiate a result set retrieval
- mysqli::$warning_count — Returns the number of warnings from the last query for the given link
The mysqli_stmt class
(PHP 5, PHP 7)
Introduction
Represents a prepared statement.
Class synopsis
mysqli_stmt::$affected_rows
mysqli_stmt_affected_rows
(PHP 5, PHP 7)
mysqli_stmt::$affected_rows -- mysqli_stmt_affected_rows — Returns the total number of rows changed, deleted, or inserted by the last executed statement
Description
Object oriented style
Procedural style
Returns the number of rows affected by INSERT,
UPDATE, or DELETE query.
This function only works with queries which update a table. In order to get the number of rows from a SELECT query, use mysqli_stmt_num_rows() instead.
Return Values
An integer greater than zero indicates the number of rows affected or retrieved. Zero indicates that no records where updated for an UPDATE/DELETE statement, no rows matched the WHERE clause in the query or that no query has yet been executed. -1 indicates that the query has returned an error. NULL indicates an invalid argument was supplied to the function.
Note:
If the number of affected rows is greater than maximal PHP int value, the number of affected rows will be returned as a string value.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* create temp table */
$mysqli->query("CREATE TEMPORARY TABLE myCountry LIKE Country");
$query = "INSERT INTO myCountry SELECT * FROM Country WHERE Code LIKE ?";
/* prepare statement */
if ($stmt = $mysqli->prepare($query)) {
/* Bind variable for placeholder */
$code = 'A%';
$stmt->bind_param("s", $code);
/* execute statement */
$stmt->execute();
printf("rows inserted: %d\n", $stmt->affected_rows);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* create temp table */
mysqli_query($link, "CREATE TEMPORARY TABLE myCountry LIKE Country");
$query = "INSERT INTO myCountry SELECT * FROM Country WHERE Code LIKE ?";
/* prepare statement */
if ($stmt = mysqli_prepare($link, $query)) {
/* Bind variable for placeholder */
$code = 'A%';
mysqli_stmt_bind_param($stmt, "s", $code);
/* execute statement */
mysqli_stmt_execute($stmt);
printf("rows inserted: %d\n", mysqli_stmt_affected_rows($stmt));
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
rows inserted: 17
See Also
- mysqli_stmt_num_rows() - Return the number of rows in statements result set
- mysqli_prepare() - Prepare an SQL statement for execution
mysqli_stmt::attr_get
mysqli_stmt_attr_get
(PHP 5, PHP 7)
mysqli_stmt::attr_get -- mysqli_stmt_attr_get — Used to get the current value of a statement attribute
Description
Object oriented style
$attr
) : intProcedural style
Gets the current value of a statement attribute.
Parameters
-
stmt -
Procedural style only: A statement identifier returned by mysqli_stmt_init().
-
attr -
The attribute that you want to get.
Return Values
Returns FALSE if the attribute is not found, otherwise returns the value of the attribute.
mysqli_stmt::attr_set
mysqli_stmt_attr_set
(PHP 5, PHP 7)
mysqli_stmt::attr_set -- mysqli_stmt_attr_set — Used to modify the behavior of a prepared statement
Description
Object oriented style
$attr
, int $mode
) : boolProcedural style
Used to modify the behavior of a prepared statement. This function may be called multiple times to set several attributes.
Parameters
-
stmt -
Procedural style only: A statement identifier returned by mysqli_stmt_init().
-
attr -
The attribute that you want to set. It can have one of the following values:
Attribute values Character Description MYSQLI_STMT_ATTR_UPDATE_MAX_LENGTH Setting to TRUEcauses mysqli_stmt_store_result() to update the metadataMYSQL_FIELD->max_lengthvalue.MYSQLI_STMT_ATTR_CURSOR_TYPE Type of cursor to open for statement when mysqli_stmt_execute() is invoked. modecan beMYSQLI_CURSOR_TYPE_NO_CURSOR(the default) orMYSQLI_CURSOR_TYPE_READ_ONLY.MYSQLI_STMT_ATTR_PREFETCH_ROWS Number of rows to fetch from server at a time when using a cursor. modecan be in the range from 1 to the maximum value of unsigned long. The default is 1.If you use the
MYSQLI_STMT_ATTR_CURSOR_TYPEoption withMYSQLI_CURSOR_TYPE_READ_ONLY, a cursor is opened for the statement when you invoke mysqli_stmt_execute(). If there is already an open cursor from a previous mysqli_stmt_execute() call, it closes the cursor before opening a new one. mysqli_stmt_reset() also closes any open cursor before preparing the statement for re-execution. mysqli_stmt_free_result() closes any open cursor.If you open a cursor for a prepared statement, mysqli_stmt_store_result() is unnecessary.
-
mode -
The value to assign to the attribute.
mysqli_stmt::bind_param
mysqli_stmt_bind_param
(PHP 5, PHP 7)
mysqli_stmt::bind_param -- mysqli_stmt_bind_param — Binds variables to a prepared statement as parameters
Description
Object oriented style
Procedural style
Bind variables for the parameter markers in the SQL statement that was passed to mysqli_prepare().
Note:
If data size of a variable exceeds max. allowed packet size (max_allowed_packet), you have to specify
bintypesand use mysqli_stmt_send_long_data() to send the data in packets.
Note:
Care must be taken when using mysqli_stmt_bind_param() in conjunction with call_user_func_array(). Note that mysqli_stmt_bind_param() requires parameters to be passed by reference, whereas call_user_func_array() can accept as a parameter a list of variables that can represent references or values.
Parameters
-
stmt -
Procedural style only: A statement identifier returned by mysqli_stmt_init().
-
types -
A string that contains one or more characters which specify the types for the corresponding bind variables:
Type specification chars Character Description i corresponding variable has type integer d corresponding variable has type double s corresponding variable has type string b corresponding variable is a blob and will be sent in packets -
var1 -
The number of variables and length of string
typesmust match the parameters in the statement.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$stmt = $mysqli->prepare("INSERT INTO CountryLanguage VALUES (?, ?, ?, ?)");
$stmt->bind_param('sssd', $code, $language, $official, $percent);
$code = 'DEU';
$language = 'Bavarian';
$official = "F";
$percent = 11.2;
/* execute prepared statement */
$stmt->execute();
printf("%d Row inserted.\n", $stmt->affected_rows);
/* close statement and connection */
$stmt->close();
/* Clean up table CountryLanguage */
$mysqli->query("DELETE FROM CountryLanguage WHERE Language='Bavarian'");
printf("%d Row deleted.\n", $mysqli->affected_rows);
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (!$link) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$stmt = mysqli_prepare($link, "INSERT INTO CountryLanguage VALUES (?, ?, ?, ?)");
mysqli_stmt_bind_param($stmt, 'sssd', $code, $language, $official, $percent);
$code = 'DEU';
$language = 'Bavarian';
$official = "F";
$percent = 11.2;
/* execute prepared statement */
mysqli_stmt_execute($stmt);
printf("%d Row inserted.\n", mysqli_stmt_affected_rows($stmt));
/* close statement and connection */
mysqli_stmt_close($stmt);
/* Clean up table CountryLanguage */
mysqli_query($link, "DELETE FROM CountryLanguage WHERE Language='Bavarian'");
printf("%d Row deleted.\n", mysqli_affected_rows($link));
/* close connection */
mysqli_close($link);
?>
The above examples will output:
1 Row inserted. 1 Row deleted.
See Also
- mysqli_stmt_bind_result() - Binds variables to a prepared statement for result storage
- mysqli_stmt_execute() - Executes a prepared Query
- mysqli_stmt_fetch() - Fetch results from a prepared statement into the bound variables
- mysqli_prepare() - Prepare an SQL statement for execution
- mysqli_stmt_send_long_data() - Send data in blocks
- mysqli_stmt_errno() - Returns the error code for the most recent statement call
- mysqli_stmt_error() - Returns a string description for last statement error
mysqli_stmt::bind_result
mysqli_stmt_bind_result
(PHP 5, PHP 7)
mysqli_stmt::bind_result -- mysqli_stmt_bind_result — Binds variables to a prepared statement for result storage
Description
Object oriented style
Procedural style
Binds columns in the result set to variables.
When mysqli_stmt_fetch() is called to fetch data, the
MySQL client/server protocol places the data for the bound columns into
the specified variables var1, ....
Note:
Note that all columns must be bound after mysqli_stmt_execute() and prior to calling mysqli_stmt_fetch(). Depending on column types bound variables can silently change to the corresponding PHP type.
A column can be bound or rebound at any time, even after a result set has been partially retrieved. The new binding takes effect the next time mysqli_stmt_fetch() is called.
Parameters
-
stmt -
Procedural style only: A statement identifier returned by mysqli_stmt_init().
-
var1 -
The variable to be bound.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* prepare statement */
if ($stmt = $mysqli->prepare("SELECT Code, Name FROM Country ORDER BY Name LIMIT 5")) {
$stmt->execute();
/* bind variables to prepared statement */
$stmt->bind_result($col1, $col2);
/* fetch values */
while ($stmt->fetch()) {
printf("%s %s\n", $col1, $col2);
}
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (!$link) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* prepare statement */
if ($stmt = mysqli_prepare($link, "SELECT Code, Name FROM Country ORDER BY Name LIMIT 5")) {
mysqli_stmt_execute($stmt);
/* bind variables to prepared statement */
mysqli_stmt_bind_result($stmt, $col1, $col2);
/* fetch values */
while (mysqli_stmt_fetch($stmt)) {
printf("%s %s\n", $col1, $col2);
}
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
AFG Afghanistan ALB Albania DZA Algeria ASM American Samoa AND Andorra
See Also
- mysqli_stmt_get_result() - Gets a result set from a prepared statement
- mysqli_stmt_bind_param() - Binds variables to a prepared statement as parameters
- mysqli_stmt_execute() - Executes a prepared Query
- mysqli_stmt_fetch() - Fetch results from a prepared statement into the bound variables
- mysqli_prepare() - Prepare an SQL statement for execution
- mysqli_stmt_prepare() - Prepare an SQL statement for execution
- mysqli_stmt_init() - Initializes a statement and returns an object for use with mysqli_stmt_prepare
- mysqli_stmt_errno() - Returns the error code for the most recent statement call
- mysqli_stmt_error() - Returns a string description for last statement error
mysqli_stmt::close
mysqli_stmt_close
(PHP 5, PHP 7)
mysqli_stmt::close -- mysqli_stmt_close — Closes a prepared statement
Description
Object oriented style
Procedural style
Closes a prepared statement. mysqli_stmt_close() also deallocates the statement handle. If the current statement has pending or unread results, this function cancels them so that the next query can be executed.
Return Values
Returns TRUE on success or FALSE on failure.
mysqli_stmt::__construct
(PHP 5, PHP 7)
mysqli_stmt::__construct — Constructs a new mysqli_stmt object
Description
This method constructs a new mysqli_stmt object.
Note:
In general, you should use either mysqli_prepare() or mysqli_stmt_init() to create a mysqli_stmt object, rather than directly instantiating the object with
new mysqli_stmt. This method (and the ability to directly instantiate mysqli_stmt objects) may be deprecated and removed in the future.
Parameters
-
link -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
-
query -
The query, as a string. If this parameter is omitted, then the constructor behaves identically to mysqli_stmt_init(), if provided, then it behaves as per mysqli_prepare().
See Also
- mysqli_prepare() - Prepare an SQL statement for execution
- mysqli_stmt_init() - Initializes a statement and returns an object for use with mysqli_stmt_prepare
mysqli_stmt::data_seek
mysqli_stmt_data_seek
(PHP 5, PHP 7)
mysqli_stmt::data_seek -- mysqli_stmt_data_seek — Seeks to an arbitrary row in statement result set
Description
Object oriented style
$offset
) : voidProcedural style
Seeks to an arbitrary result pointer in the statement result set.
mysqli_stmt_store_result() must be called prior to mysqli_stmt_data_seek().
Parameters
-
stmt -
Procedural style only: A statement identifier returned by mysqli_stmt_init().
-
offset -
Must be between zero and the total number of rows minus one (0.. mysqli_stmt_num_rows() - 1).
Return Values
No value is returned.
Examples
Example #1 Object oriented style
<?php
/* Open a connection */
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER BY Name";
if ($stmt = $mysqli->prepare($query)) {
/* execute query */
$stmt->execute();
/* bind result variables */
$stmt->bind_result($name, $code);
/* store result */
$stmt->store_result();
/* seek to row no. 400 */
$stmt->data_seek(399);
/* fetch values */
$stmt->fetch();
printf ("City: %s Countrycode: %s\n", $name, $code);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
/* Open a connection */
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER BY Name";
if ($stmt = mysqli_prepare($link, $query)) {
/* execute query */
mysqli_stmt_execute($stmt);
/* bind result variables */
mysqli_stmt_bind_result($stmt, $name, $code);
/* store result */
mysqli_stmt_store_result($stmt);
/* seek to row no. 400 */
mysqli_stmt_data_seek($stmt, 399);
/* fetch values */
mysqli_stmt_fetch($stmt);
printf ("City: %s Countrycode: %s\n", $name, $code);
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
City: Benin City Countrycode: NGA
mysqli_stmt::$errno
mysqli_stmt_errno
(PHP 5, PHP 7)
mysqli_stmt::$errno -- mysqli_stmt_errno — Returns the error code for the most recent statement call
Description
Object oriented style
Procedural style
Returns the error code for the most recently invoked statement function that can succeed or fail.
Client error message numbers are listed in the MySQL errmsg.h header file, server error message numbers are listed in mysqld_error.h. In the MySQL source distribution you can find a complete list of error messages and error numbers in the file Docs/mysqld_error.txt.
Return Values
An error code value. Zero means no error occurred.
Examples
Example #1 Object oriented style
<?php
/* Open a connection */
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$mysqli->query("CREATE TABLE myCountry LIKE Country");
$mysqli->query("INSERT INTO myCountry SELECT * FROM Country");
$query = "SELECT Name, Code FROM myCountry ORDER BY Name";
if ($stmt = $mysqli->prepare($query)) {
/* drop table */
$mysqli->query("DROP TABLE myCountry");
/* execute query */
$stmt->execute();
printf("Error: %d.\n", $stmt->errno);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
/* Open a connection */
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
mysqli_query($link, "CREATE TABLE myCountry LIKE Country");
mysqli_query($link, "INSERT INTO myCountry SELECT * FROM Country");
$query = "SELECT Name, Code FROM myCountry ORDER BY Name";
if ($stmt = mysqli_prepare($link, $query)) {
/* drop table */
mysqli_query($link, "DROP TABLE myCountry");
/* execute query */
mysqli_stmt_execute($stmt);
printf("Error: %d.\n", mysqli_stmt_errno($stmt));
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Error: 1146.
See Also
- mysqli_stmt_error() - Returns a string description for last statement error
- mysqli_stmt_sqlstate() - Returns SQLSTATE error from previous statement operation
mysqli_stmt::$error_list
mysqli_stmt_error_list
(PHP 5 >= 5.4.0, PHP 7)
mysqli_stmt::$error_list -- mysqli_stmt_error_list — Returns a list of errors from the last statement executed
Description
Object oriented style
Procedural style
Returns an array of errors for the most recently invoked statement function that can succeed or fail.
Return Values
A list of errors, each as an associative array containing the errno, error, and sqlstate.
Examples
Example #1 Object oriented style
<?php
/* Open a connection */
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$mysqli->query("CREATE TABLE myCountry LIKE Country");
$mysqli->query("INSERT INTO myCountry SELECT * FROM Country");
$query = "SELECT Name, Code FROM myCountry ORDER BY Name";
if ($stmt = $mysqli->prepare($query)) {
/* drop table */
$mysqli->query("DROP TABLE myCountry");
/* execute query */
$stmt->execute();
echo "Error:\n";
print_r($stmt->error_list);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
/* Open a connection */
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
mysqli_query($link, "CREATE TABLE myCountry LIKE Country");
mysqli_query($link, "INSERT INTO myCountry SELECT * FROM Country");
$query = "SELECT Name, Code FROM myCountry ORDER BY Name";
if ($stmt = mysqli_prepare($link, $query)) {
/* drop table */
mysqli_query($link, "DROP TABLE myCountry");
/* execute query */
mysqli_stmt_execute($stmt);
echo "Error:\n";
print_r(mysql_stmt_error_list($stmt));
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Array
(
[0] => Array
(
[errno] => 1146
[sqlstate] => 42S02
[error] => Table 'world.myCountry' doesn't exist
)
)
See Also
- mysqli_stmt_error() - Returns a string description for last statement error
- mysqli_stmt_errno() - Returns the error code for the most recent statement call
- mysqli_stmt_sqlstate() - Returns SQLSTATE error from previous statement operation
mysqli_stmt::$error
mysqli_stmt_error
(PHP 5, PHP 7)
mysqli_stmt::$error -- mysqli_stmt_error — Returns a string description for last statement error
Description
Object oriented style
Procedural style
Returns a string containing the error message for the most recently invoked statement function that can succeed or fail.
Return Values
A string that describes the error. An empty string if no error occurred.
Examples
Example #1 Object oriented style
<?php
/* Open a connection */
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$mysqli->query("CREATE TABLE myCountry LIKE Country");
$mysqli->query("INSERT INTO myCountry SELECT * FROM Country");
$query = "SELECT Name, Code FROM myCountry ORDER BY Name";
if ($stmt = $mysqli->prepare($query)) {
/* drop table */
$mysqli->query("DROP TABLE myCountry");
/* execute query */
$stmt->execute();
printf("Error: %s.\n", $stmt->error);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
/* Open a connection */
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
mysqli_query($link, "CREATE TABLE myCountry LIKE Country");
mysqli_query($link, "INSERT INTO myCountry SELECT * FROM Country");
$query = "SELECT Name, Code FROM myCountry ORDER BY Name";
if ($stmt = mysqli_prepare($link, $query)) {
/* drop table */
mysqli_query($link, "DROP TABLE myCountry");
/* execute query */
mysqli_stmt_execute($stmt);
printf("Error: %s.\n", mysqli_stmt_error($stmt));
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Error: Table 'world.myCountry' doesn't exist.
See Also
- mysqli_stmt_errno() - Returns the error code for the most recent statement call
- mysqli_stmt_sqlstate() - Returns SQLSTATE error from previous statement operation
mysqli_stmt::execute
mysqli_stmt_execute
(PHP 5, PHP 7)
mysqli_stmt::execute -- mysqli_stmt_execute — Executes a prepared Query
Description
Object oriented style
Procedural style
Executes a query that has been previously prepared using the mysqli_prepare() function. When executed any parameter markers which exist will automatically be replaced with the appropriate data.
If the statement is UPDATE, DELETE,
or INSERT, the total number of affected rows can be
determined by using the mysqli_stmt_affected_rows()
function. Likewise, if the query yields a result set the
mysqli_stmt_fetch() function is used.
Note:
When using mysqli_stmt_execute(), the mysqli_stmt_fetch() function must be used to fetch the data prior to performing any additional queries.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$mysqli->query("CREATE TABLE myCity LIKE City");
/* Prepare an insert statement */
$query = "INSERT INTO myCity (Name, CountryCode, District) VALUES (?,?,?)";
$stmt = $mysqli->prepare($query);
$stmt->bind_param("sss", $val1, $val2, $val3);
$val1 = 'Stuttgart';
$val2 = 'DEU';
$val3 = 'Baden-Wuerttemberg';
/* Execute the statement */
$stmt->execute();
$val1 = 'Bordeaux';
$val2 = 'FRA';
$val3 = 'Aquitaine';
/* Execute the statement */
$stmt->execute();
/* close statement */
$stmt->close();
/* retrieve all rows from myCity */
$query = "SELECT Name, CountryCode, District FROM myCity";
if ($result = $mysqli->query($query)) {
while ($row = $result->fetch_row()) {
printf("%s (%s,%s)\n", $row[0], $row[1], $row[2]);
}
/* free result set */
$result->close();
}
/* remove table */
$mysqli->query("DROP TABLE myCity");
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
mysqli_query($link, "CREATE TABLE myCity LIKE City");
/* Prepare an insert statement */
$query = "INSERT INTO myCity (Name, CountryCode, District) VALUES (?,?,?)";
$stmt = mysqli_prepare($link, $query);
mysqli_stmt_bind_param($stmt, "sss", $val1, $val2, $val3);
$val1 = 'Stuttgart';
$val2 = 'DEU';
$val3 = 'Baden-Wuerttemberg';
/* Execute the statement */
mysqli_stmt_execute($stmt);
$val1 = 'Bordeaux';
$val2 = 'FRA';
$val3 = 'Aquitaine';
/* Execute the statement */
mysqli_stmt_execute($stmt);
/* close statement */
mysqli_stmt_close($stmt);
/* retrieve all rows from myCity */
$query = "SELECT Name, CountryCode, District FROM myCity";
if ($result = mysqli_query($link, $query)) {
while ($row = mysqli_fetch_row($result)) {
printf("%s (%s,%s)\n", $row[0], $row[1], $row[2]);
}
/* free result set */
mysqli_free_result($result);
}
/* remove table */
mysqli_query($link, "DROP TABLE myCity");
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Stuttgart (DEU,Baden-Wuerttemberg) Bordeaux (FRA,Aquitaine)
See Also
- mysqli_prepare() - Prepare an SQL statement for execution
- mysqli_stmt_bind_param() - Binds variables to a prepared statement as parameters
- mysqli_stmt_get_result() - Gets a result set from a prepared statement
mysqli_stmt::fetch
mysqli_stmt_fetch
(PHP 5, PHP 7)
mysqli_stmt::fetch -- mysqli_stmt_fetch — Fetch results from a prepared statement into the bound variables
Description
Object oriented style
Procedural style
Fetch the result from a prepared statement into the variables bound by mysqli_stmt_bind_result().
Note:
Note that all columns must be bound by the application before calling mysqli_stmt_fetch().
Note:
Data are transferred unbuffered without calling mysqli_stmt_store_result() which can decrease performance (but reduces memory cost).
Return Values
| Value | Description |
|---|---|
TRUE |
Success. Data has been fetched |
FALSE |
Error occurred |
NULL |
No more rows/data exists or data truncation occurred |
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 150,5";
if ($stmt = $mysqli->prepare($query)) {
/* execute statement */
$stmt->execute();
/* bind result variables */
$stmt->bind_result($name, $code);
/* fetch values */
while ($stmt->fetch()) {
printf ("%s (%s)\n", $name, $code);
}
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 150,5";
if ($stmt = mysqli_prepare($link, $query)) {
/* execute statement */
mysqli_stmt_execute($stmt);
/* bind result variables */
mysqli_stmt_bind_result($stmt, $name, $code);
/* fetch values */
while (mysqli_stmt_fetch($stmt)) {
printf ("%s (%s)\n", $name, $code);
}
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Rockford (USA) Tallahassee (USA) Salinas (USA) Santa Clarita (USA) Springfield (USA)
See Also
- mysqli_prepare() - Prepare an SQL statement for execution
- mysqli_stmt_errno() - Returns the error code for the most recent statement call
- mysqli_stmt_error() - Returns a string description for last statement error
- mysqli_stmt_bind_result() - Binds variables to a prepared statement for result storage
mysqli_stmt::$field_count
mysqli_stmt_field_count
(PHP 5, PHP 7)
mysqli_stmt::$field_count -- mysqli_stmt_field_count — Returns the number of field in the given statement
Description
Object oriented style
Procedural style
This function is currently not documented; only its argument list is available.
mysqli_stmt::free_result
mysqli_stmt_free_result
(PHP 5, PHP 7)
mysqli_stmt::free_result -- mysqli_stmt_free_result — Frees stored result memory for the given statement handle
Description
Object oriented style
Procedural style
Frees the result memory associated with the statement, which was allocated by mysqli_stmt_store_result().
Return Values
No value is returned.
mysqli_stmt::get_result
mysqli_stmt_get_result
(PHP 5 >= 5.3.0, PHP 7)
mysqli_stmt::get_result -- mysqli_stmt_get_result — Gets a result set from a prepared statement
Description
Object oriented style
Procedural style
Call to return a result set from a prepared statement query.
Return Values
Returns a resultset for successful SELECT queries, or FALSE for other DML
queries or on failure. The mysqli_errno() function can be
used to distinguish between the two types of failure.
MySQL Native Driver Only
Available only with mysqlnd.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("127.0.0.1", "user", "password", "world");
if($mysqli->connect_error)
{
die("$mysqli->connect_errno: $mysqli->connect_error");
}
$query = "SELECT Name, Population, Continent FROM Country WHERE Continent=? ORDER BY Name LIMIT 1";
$stmt = $mysqli->stmt_init();
if(!$stmt->prepare($query))
{
print "Failed to prepare statement\n";
}
else
{
$stmt->bind_param("s", $continent);
$continent_array = array('Europe','Africa','Asia','North America');
foreach($continent_array as $continent)
{
$stmt->execute();
$result = $stmt->get_result();
while ($row = $result->fetch_array(MYSQLI_NUM))
{
foreach ($row as $r)
{
print "$r ";
}
print "\n";
}
}
}
$stmt->close();
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("127.0.0.1", "user", "password", "world");
if (!$link)
{
$error = mysqli_connect_error();
$errno = mysqli_connect_errno();
print "$errno: $error\n";
exit();
}
$query = "SELECT Name, Population, Continent FROM Country WHERE Continent=? ORDER BY Name LIMIT 1";
$stmt = mysqli_stmt_init($link);
if(!mysqli_stmt_prepare($stmt, $query))
{
print "Failed to prepare statement\n";
}
else
{
mysqli_stmt_bind_param($stmt, "s", $continent);
$continent_array = array('Europe','Africa','Asia','North America');
foreach($continent_array as $continent)
{
mysqli_stmt_execute($stmt);
$result = mysqli_stmt_get_result($stmt);
while ($row = mysqli_fetch_array($result, MYSQLI_NUM))
{
foreach ($row as $r)
{
print "$r ";
}
print "\n";
}
}
}
mysqli_stmt_close($stmt);
mysqli_close($link);
?>
The above examples will output:
Albania 3401200 Europe Algeria 31471000 Africa Afghanistan 22720000 Asia Anguilla 8000 North America
See Also
- mysqli_prepare() - Prepare an SQL statement for execution
- mysqli_stmt_result_metadata() - Returns result set metadata from a prepared statement
- mysqli_stmt_fetch() - Fetch results from a prepared statement into the bound variables
- mysqli_fetch_array() - Fetch a result row as an associative, a numeric array, or both
- mysqli_stmt_store_result() - Transfers a result set from a prepared statement
- mysqli_errno() - Returns the error code for the most recent function call
mysqli_stmt::get_warnings
mysqli_stmt_get_warnings
(PHP 5 >= 5.1.0, PHP 7)
mysqli_stmt::get_warnings -- mysqli_stmt_get_warnings — Get result of SHOW WARNINGS
Description
Object oriented style
Procedural style
This function is currently not documented; only its argument list is available.
mysqli_stmt::$insert_id
mysqli_stmt_insert_id
(PHP 5, PHP 7)
mysqli_stmt::$insert_id -- mysqli_stmt_insert_id — Get the ID generated from the previous INSERT operation
Description
Object oriented style
Procedural style
This function is currently not documented; only its argument list is available.
mysqli_stmt::more_results
mysqli_stmt_more_results
(PHP 5 >= 5.3.0, PHP 7)
mysqli_stmt::more_results -- mysqli_stmt_more_results — Check if there are more query results from a multiple query
Description
Object oriented style
Procedural style:
$stmt
) : boolChecks if there are more query results from a multiple query.
Return Values
Returns TRUE if more results exist, otherwise FALSE.
MySQL Native Driver Only
Available only with mysqlnd.
See Also
- mysqli_stmt::next_result() - Reads the next result from a multiple query
- mysqli::multi_query() - Performs a query on the database
mysqli_stmt::next_result
mysqli_stmt_next_result
(PHP 5 >= 5.3.0, PHP 7)
mysqli_stmt::next_result -- mysqli_stmt_next_result — Reads the next result from a multiple query
Description
Object oriented style
Procedural style:
$stmt
) : boolReads the next result from a multiple query.
Return Values
Returns TRUE on success or FALSE on failure.
Errors/Exceptions
Emits an E_STRICT level error if a result set does
not exist, and suggests using mysqli_stmt::more_results()
in these cases, before calling mysqli_stmt::next_result().
MySQL Native Driver Only
Available only with mysqlnd.
See Also
- mysqli_stmt::more_results() - Check if there are more query results from a multiple query
- mysqli::multi_query() - Performs a query on the database
mysqli_stmt::$num_rows
mysqli_stmt::num_rows
mysqli_stmt_num_rows
(PHP 5, PHP 7)
mysqli_stmt::$num_rows -- mysqli_stmt::num_rows -- mysqli_stmt_num_rows — Return the number of rows in statements result set
Description
Object oriented style
Procedural style
Returns the number of rows in the result set. The use of mysqli_stmt_num_rows() depends on whether or not you used mysqli_stmt_store_result() to buffer the entire result set in the statement handle.
If you use mysqli_stmt_store_result(), mysqli_stmt_num_rows() may be called immediately.
Return Values
An integer representing the number of rows in result set.
Examples
Example #1 Object oriented style
<?php
/* Open a connection */
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER BY Name LIMIT 20";
if ($stmt = $mysqli->prepare($query)) {
/* execute query */
$stmt->execute();
/* store result */
$stmt->store_result();
printf("Number of rows: %d.\n", $stmt->num_rows);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
/* Open a connection */
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER BY Name LIMIT 20";
if ($stmt = mysqli_prepare($link, $query)) {
/* execute query */
mysqli_stmt_execute($stmt);
/* store result */
mysqli_stmt_store_result($stmt);
printf("Number of rows: %d.\n", mysqli_stmt_num_rows($stmt));
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Number of rows: 20.
See Also
- mysqli_stmt_affected_rows() - Returns the total number of rows changed, deleted, or inserted by the last executed statement
- mysqli_prepare() - Prepare an SQL statement for execution
- mysqli_stmt_store_result() - Transfers a result set from a prepared statement
mysqli_stmt::$param_count
mysqli_stmt_param_count
(PHP 5, PHP 7)
mysqli_stmt::$param_count -- mysqli_stmt_param_count — Returns the number of parameter for the given statement
Description
Object oriented style
Procedural style
Returns the number of parameter markers present in the prepared statement.
Return Values
Returns an integer representing the number of parameters.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if ($stmt = $mysqli->prepare("SELECT Name FROM Country WHERE Name=? OR Code=?")) {
$marker = $stmt->param_count;
printf("Statement has %d markers.\n", $marker);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if ($stmt = mysqli_prepare($link, "SELECT Name FROM Country WHERE Name=? OR Code=?")) {
$marker = mysqli_stmt_param_count($stmt);
printf("Statement has %d markers.\n", $marker);
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Statement has 2 markers.
mysqli_stmt::prepare
mysqli_stmt_prepare
(PHP 5, PHP 7)
mysqli_stmt::prepare -- mysqli_stmt_prepare — Prepare an SQL statement for execution
Description
Object oriented style
Procedural style
Prepares the SQL query pointed to by the null-terminated string query.
The parameter markers must be bound to application variables using mysqli_stmt_bind_param() and/or mysqli_stmt_bind_result() before executing the statement or fetching rows.
Note:
In the case where you pass a statement to mysqli_stmt_prepare() that is longer than
max_allowed_packetof the server, the returned error codes are different depending on whether you are using MySQL Native Driver (mysqlnd) or MySQL Client Library (libmysqlclient). The behavior is as follows:
mysqlndon Linux returns an error code of 1153. The error message meansgot a packet bigger than.max_allowed_packetbytes
mysqlndon Windows returns an error code 2006. This error message meansserver has gone away.
libmysqlclienton all platforms returns an error code 2006. This error message meansserver has gone away.
Parameters
-
stmt -
Procedural style only: A statement identifier returned by mysqli_stmt_init().
-
query -
The query, as a string. It must consist of a single SQL statement.
You can include one or more parameter markers in the SQL statement by embedding question mark (
?) characters at the appropriate positions.Note:
You should not add a terminating semicolon or
\gto the statement.Note:
The markers are legal only in certain places in SQL statements. For example, they are allowed in the VALUES() list of an INSERT statement (to specify column values for a row), or in a comparison with a column in a WHERE clause to specify a comparison value.
However, they are not allowed for identifiers (such as table or column names), in the select list that names the columns to be returned by a SELECT statement), or to specify both operands of a binary operator such as the
=equal sign. The latter restriction is necessary because it would be impossible to determine the parameter type. In general, parameters are legal only in Data Manipulation Language (DML) statements, and not in Data Definition Language (DDL) statements.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$city = "Amersfoort";
/* create a prepared statement */
$stmt = $mysqli->stmt_init();
if ($stmt->prepare("SELECT District FROM City WHERE Name=?")) {
/* bind parameters for markers */
$stmt->bind_param("s", $city);
/* execute query */
$stmt->execute();
/* bind result variables */
$stmt->bind_result($district);
/* fetch value */
$stmt->fetch();
printf("%s is in district %s\n", $city, $district);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$city = "Amersfoort";
/* create a prepared statement */
$stmt = mysqli_stmt_init($link);
if (mysqli_stmt_prepare($stmt, 'SELECT District FROM City WHERE Name=?')) {
/* bind parameters for markers */
mysqli_stmt_bind_param($stmt, "s", $city);
/* execute query */
mysqli_stmt_execute($stmt);
/* bind result variables */
mysqli_stmt_bind_result($stmt, $district);
/* fetch value */
mysqli_stmt_fetch($stmt);
printf("%s is in district %s\n", $city, $district);
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Amersfoort is in district Utrecht
See Also
- mysqli_stmt_init() - Initializes a statement and returns an object for use with mysqli_stmt_prepare
- mysqli_stmt_execute() - Executes a prepared Query
- mysqli_stmt_fetch() - Fetch results from a prepared statement into the bound variables
- mysqli_stmt_bind_param() - Binds variables to a prepared statement as parameters
- mysqli_stmt_bind_result() - Binds variables to a prepared statement for result storage
- mysqli_stmt_get_result() - Gets a result set from a prepared statement
- mysqli_stmt_close() - Closes a prepared statement
mysqli_stmt::reset
mysqli_stmt_reset
(PHP 5, PHP 7)
mysqli_stmt::reset -- mysqli_stmt_reset — Resets a prepared statement
Description
Object oriented style
Procedural style
Resets a prepared statement on client and server to state after prepare.
It resets the statement on the server, data sent using mysqli_stmt_send_long_data(), unbuffered result sets and current errors. It does not clear bindings or stored result sets. Stored result sets will be cleared when executing the prepared statement (or closing it).
To prepare a statement with another query use function mysqli_stmt_prepare().
Return Values
Returns TRUE on success or FALSE on failure.
mysqli_stmt::result_metadata
mysqli_stmt_result_metadata
(PHP 5, PHP 7)
mysqli_stmt::result_metadata -- mysqli_stmt_result_metadata — Returns result set metadata from a prepared statement
Description
Object oriented style
Procedural style
If a statement passed to mysqli_prepare() is one that produces a result set, mysqli_stmt_result_metadata() returns the result object that can be used to process the meta information such as total number of fields and individual field information.
Note:
This result set pointer can be passed as an argument to any of the field-based functions that process result set metadata, such as:
The result set structure should be freed when you are done with it, which you can do by passing it to mysqli_free_result()
Note:
The result set returned by mysqli_stmt_result_metadata() contains only metadata. It does not contain any row results. The rows are obtained by using the statement handle with mysqli_stmt_fetch().
Return Values
Returns a result object or FALSE if an error occurred.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "test");
$mysqli->query("DROP TABLE IF EXISTS friends");
$mysqli->query("CREATE TABLE friends (id int, name varchar(20))");
$mysqli->query("INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");
$stmt = $mysqli->prepare("SELECT id, name FROM friends");
$stmt->execute();
/* get resultset for metadata */
$result = $stmt->result_metadata();
/* retrieve field information from metadata result set */
$field = $result->fetch_field();
printf("Fieldname: %s\n", $field->name);
/* close resultset */
$result->close();
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "test");
mysqli_query($link, "DROP TABLE IF EXISTS friends");
mysqli_query($link, "CREATE TABLE friends (id int, name varchar(20))");
mysqli_query($link, "INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");
$stmt = mysqli_prepare($link, "SELECT id, name FROM friends");
mysqli_stmt_execute($stmt);
/* get resultset for metadata */
$result = mysqli_stmt_result_metadata($stmt);
/* retrieve field information from metadata result set */
$field = mysqli_fetch_field($result);
printf("Fieldname: %s\n", $field->name);
/* close resultset */
mysqli_free_result($result);
/* close connection */
mysqli_close($link);
?>
See Also
- mysqli_prepare() - Prepare an SQL statement for execution
- mysqli_free_result() - Frees the memory associated with a result
mysqli_stmt::send_long_data
mysqli_stmt_send_long_data
(PHP 5, PHP 7)
mysqli_stmt::send_long_data -- mysqli_stmt_send_long_data — Send data in blocks
Description
Object oriented style
$param_nr
, string $data
) : boolProcedural style
Allows to send parameter data to the server in pieces (or chunks), e.g. if the
size of a blob exceeds the size of max_allowed_packet.
This function can be called multiple times to send the parts of a character or
binary data value for a column, which must be one of the TEXT or BLOB datatypes.
Parameters
-
stmt -
Procedural style only: A statement identifier returned by mysqli_stmt_init().
-
param_nr -
Indicates which parameter to associate the data with. Parameters are numbered beginning with 0.
-
data -
A string containing data to be sent.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 Object oriented style
<?php
$stmt = $mysqli->prepare("INSERT INTO messages (message) VALUES (?)");
$null = NULL;
$stmt->bind_param("b", $null);
$fp = fopen("messages.txt", "r");
while (!feof($fp)) {
$stmt->send_long_data(0, fread($fp, 8192));
}
fclose($fp);
$stmt->execute();
?>
See Also
- mysqli_prepare() - Prepare an SQL statement for execution
- mysqli_stmt_bind_param() - Binds variables to a prepared statement as parameters
mysqli_stmt::$sqlstate
mysqli_stmt_sqlstate
(PHP 5, PHP 7)
mysqli_stmt::$sqlstate -- mysqli_stmt_sqlstate — Returns SQLSTATE error from previous statement operation
Description
Object oriented style
Procedural style
Returns a string containing the SQLSTATE error code
for the most recently invoked prepared statement function that can succeed or fail.
The error code consists of five characters. '00000' means no error.
The values are specified by ANSI SQL and ODBC. For a list of possible values, see
» http://dev.mysql.com/doc/mysql/en/error-handling.html.
Return Values
Returns a string containing the SQLSTATE error code for the last error.
The error code consists of five characters. '00000' means no error.
Notes
Note:
Note that not all MySQL errors are yet mapped to SQLSTATE's. The value
HY000(general error) is used for unmapped errors.
Examples
Example #1 Object oriented style
<?php
/* Open a connection */
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$mysqli->query("CREATE TABLE myCountry LIKE Country");
$mysqli->query("INSERT INTO myCountry SELECT * FROM Country");
$query = "SELECT Name, Code FROM myCountry ORDER BY Name";
if ($stmt = $mysqli->prepare($query)) {
/* drop table */
$mysqli->query("DROP TABLE myCountry");
/* execute query */
$stmt->execute();
printf("Error: %s.\n", $stmt->sqlstate);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
/* Open a connection */
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
mysqli_query($link, "CREATE TABLE myCountry LIKE Country");
mysqli_query($link, "INSERT INTO myCountry SELECT * FROM Country");
$query = "SELECT Name, Code FROM myCountry ORDER BY Name";
if ($stmt = mysqli_prepare($link, $query)) {
/* drop table */
mysqli_query($link, "DROP TABLE myCountry");
/* execute query */
mysqli_stmt_execute($stmt);
printf("Error: %s.\n", mysqli_stmt_sqlstate($stmt));
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Error: 42S02.
See Also
- mysqli_stmt_errno() - Returns the error code for the most recent statement call
- mysqli_stmt_error() - Returns a string description for last statement error
mysqli_stmt::store_result
mysqli_stmt_store_result
(PHP 5, PHP 7)
mysqli_stmt::store_result -- mysqli_stmt_store_result — Transfers a result set from a prepared statement
Description
Object oriented style
Procedural style
You must call mysqli_stmt_store_result() for every query that
successfully produces a result set (SELECT, SHOW, DESCRIBE, EXPLAIN),
if and only if you want to buffer the complete result set by the client,
so that the subsequent mysqli_stmt_fetch() call returns buffered data.
Note:
It is unnecessary to call mysqli_stmt_store_result() for other queries, but if you do, it will not harm or cause any notable performance loss in all cases. You can detect whether the query produced a result set by checking if mysqli_stmt_result_metadata() returns
FALSE.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 Object oriented style
<?php
/* Open a connection */
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER BY Name LIMIT 20";
if ($stmt = $mysqli->prepare($query)) {
/* execute query */
$stmt->execute();
/* store result */
$stmt->store_result();
printf("Number of rows: %d.\n", $stmt->num_rows);
/* free result */
$stmt->free_result();
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
/* Open a connection */
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER BY Name LIMIT 20";
if ($stmt = mysqli_prepare($link, $query)) {
/* execute query */
mysqli_stmt_execute($stmt);
/* store result */
mysqli_stmt_store_result($stmt);
printf("Number of rows: %d.\n", mysqli_stmt_num_rows($stmt));
/* free result */
mysqli_stmt_free_result($stmt);
/* close statement */
mysqli_stmt_close($stmt);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Number of rows: 20.
See Also
- mysqli_prepare() - Prepare an SQL statement for execution
- mysqli_stmt_result_metadata() - Returns result set metadata from a prepared statement
- mysqli_stmt_fetch() - Fetch results from a prepared statement into the bound variables
Table of Contents
- mysqli_stmt::$affected_rows — Returns the total number of rows changed, deleted, or inserted by the last executed statement
- mysqli_stmt::attr_get — Used to get the current value of a statement attribute
- mysqli_stmt::attr_set — Used to modify the behavior of a prepared statement
- mysqli_stmt::bind_param — Binds variables to a prepared statement as parameters
- mysqli_stmt::bind_result — Binds variables to a prepared statement for result storage
- mysqli_stmt::close — Closes a prepared statement
- mysqli_stmt::__construct — Constructs a new mysqli_stmt object
- mysqli_stmt::data_seek — Seeks to an arbitrary row in statement result set
- mysqli_stmt::$errno — Returns the error code for the most recent statement call
- mysqli_stmt::$error_list — Returns a list of errors from the last statement executed
- mysqli_stmt::$error — Returns a string description for last statement error
- mysqli_stmt::execute — Executes a prepared Query
- mysqli_stmt::fetch — Fetch results from a prepared statement into the bound variables
- mysqli_stmt::$field_count — Returns the number of field in the given statement
- mysqli_stmt::free_result — Frees stored result memory for the given statement handle
- mysqli_stmt::get_result — Gets a result set from a prepared statement
- mysqli_stmt::get_warnings — Get result of SHOW WARNINGS
- mysqli_stmt::$insert_id — Get the ID generated from the previous INSERT operation
- mysqli_stmt::more_results — Check if there are more query results from a multiple query
- mysqli_stmt::next_result — Reads the next result from a multiple query
- mysqli_stmt::$num_rows — Return the number of rows in statements result set
- mysqli_stmt::$param_count — Returns the number of parameter for the given statement
- mysqli_stmt::prepare — Prepare an SQL statement for execution
- mysqli_stmt::reset — Resets a prepared statement
- mysqli_stmt::result_metadata — Returns result set metadata from a prepared statement
- mysqli_stmt::send_long_data — Send data in blocks
- mysqli_stmt::$sqlstate — Returns SQLSTATE error from previous statement operation
- mysqli_stmt::store_result — Transfers a result set from a prepared statement
The mysqli_result class
(PHP 5, PHP 7)
Introduction
Represents the result set obtained from a query against the database.
Changelog
| Version | Description |
|---|---|
| 5.4.0 | Iterator support was added, as mysqli_result now implements Traversable. |
Class synopsis
mysqli_result::$current_field
mysqli_field_tell
(PHP 5, PHP 7)
mysqli_result::$current_field -- mysqli_field_tell — Get current field offset of a result pointer
Description
Object oriented style
Procedural style
Returns the position of the field cursor used for the last mysqli_fetch_field() call. This value can be used as an argument to mysqli_field_seek().
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
Return Values
Returns current offset of field cursor.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5";
if ($result = $mysqli->query($query)) {
/* Get field information for all columns */
while ($finfo = $result->fetch_field()) {
/* get fieldpointer offset */
$currentfield = $result->current_field;
printf("Column %d:\n", $currentfield);
printf("Name: %s\n", $finfo->name);
printf("Table: %s\n", $finfo->table);
printf("max. Len: %d\n", $finfo->max_length);
printf("Flags: %d\n", $finfo->flags);
printf("Type: %d\n\n", $finfo->type);
}
$result->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5";
if ($result = mysqli_query($link, $query)) {
/* Get field information for all fields */
while ($finfo = mysqli_fetch_field($result)) {
/* get fieldpointer offset */
$currentfield = mysqli_field_tell($result);
printf("Column %d:\n", $currentfield);
printf("Name: %s\n", $finfo->name);
printf("Table: %s\n", $finfo->table);
printf("max. Len: %d\n", $finfo->max_length);
printf("Flags: %d\n", $finfo->flags);
printf("Type: %d\n\n", $finfo->type);
}
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Column 1: Name: Name Table: Country max. Len: 11 Flags: 1 Type: 254 Column 2: Name: SurfaceArea Table: Country max. Len: 10 Flags: 32769 Type: 4
See Also
- mysqli_fetch_field() - Returns the next field in the result set
- mysqli_field_seek() - Set result pointer to a specified field offset
mysqli_result::data_seek
mysqli_data_seek
(PHP 5, PHP 7)
mysqli_result::data_seek -- mysqli_data_seek — Adjusts the result pointer to an arbitrary row in the result
Description
Object oriented style
$offset
) : boolProcedural style
The mysqli_data_seek() function seeks to an arbitrary
result pointer specified by the offset in the
result set.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
-
offset -
The field offset. Must be between zero and the total number of rows minus one (0..mysqli_num_rows() - 1).
Return Values
Returns TRUE on success or FALSE on failure.
Notes
Note:
This function can only be used with buffered results attained from the use of the mysqli_store_result() or mysqli_query() functions.
Examples
Example #1 Object oriented style
<?php
/* Open a connection */
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER BY Name";
if ($result = $mysqli->query($query)) {
/* seek to row no. 400 */
$result->data_seek(399);
/* fetch row */
$row = $result->fetch_row();
printf ("City: %s Countrycode: %s\n", $row[0], $row[1]);
/* free result set*/
$result->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
/* Open a connection */
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (!$link) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER BY Name";
if ($result = mysqli_query($link, $query)) {
/* seek to row no. 400 */
mysqli_data_seek($result, 399);
/* fetch row */
$row = mysqli_fetch_row($result);
printf ("City: %s Countrycode: %s\n", $row[0], $row[1]);
/* free result set*/
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
City: Benin City Countrycode: NGA
See Also
- mysqli_store_result() - Transfers a result set from the last query
- mysqli_fetch_row() - Get a result row as an enumerated array
- mysqli_fetch_array() - Fetch a result row as an associative, a numeric array, or both
- mysqli_fetch_assoc() - Fetch a result row as an associative array
- mysqli_fetch_object() - Returns the current row of a result set as an object
- mysqli_query() - Performs a query on the database
- mysqli_num_rows() - Gets the number of rows in a result
mysqli_result::fetch_all
mysqli_fetch_all
(PHP 5 >= 5.3.0, PHP 7)
mysqli_result::fetch_all -- mysqli_fetch_all — Fetches all result rows as an associative array, a numeric array, or both
Description
Object oriented style
Procedural style
mysqli_fetch_all() fetches all result rows and returns the result set as an associative array, a numeric array, or both.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
-
resulttype -
This optional parameter is a constant indicating what type of array should be produced from the current row data. The possible values for this parameter are the constants
MYSQLI_ASSOC,MYSQLI_NUM, orMYSQLI_BOTH.
Return Values
Returns an array of associative or numeric arrays holding result rows.
MySQL Native Driver Only
Available only with mysqlnd.
As mysqli_fetch_all() returns all the rows as an array in a single step, it may consume more memory than some similar functions such as mysqli_fetch_array(), which only returns one row at a time from the result set. Further, if you need to iterate over the result set, you will need a looping construct that will further impact performance. For these reasons mysqli_fetch_all() should only be used in those situations where the fetched result set will be sent to another layer for processing.
See Also
- mysqli_fetch_array() - Fetch a result row as an associative, a numeric array, or both
- mysqli_query() - Performs a query on the database
mysqli_result::fetch_array
mysqli_fetch_array
(PHP 5, PHP 7)
mysqli_result::fetch_array -- mysqli_fetch_array — Fetch a result row as an associative, a numeric array, or both
Description
Object oriented style
Procedural style
Returns an array that corresponds to the fetched row or NULL if there
are no more rows for the resultset represented by the
result parameter.
mysqli_fetch_array() is an extended version of the mysqli_fetch_row() function. In addition to storing the data in the numeric indices of the result array, the mysqli_fetch_array() function can also store the data in associative indices, using the field names of the result set as keys.
Note: Field names returned by this function are case-sensitive.
Note: This function sets NULL fields to the PHP
NULLvalue.
If two or more columns of the result have the same field names, the last column will take precedence and overwrite the earlier data. In order to access multiple columns with the same name, the numerically indexed version of the row must be used.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
-
resulttype -
This optional parameter is a constant indicating what type of array should be produced from the current row data. The possible values for this parameter are the constants
MYSQLI_ASSOC,MYSQLI_NUM, orMYSQLI_BOTH.By using the
MYSQLI_ASSOCconstant this function will behave identically to the mysqli_fetch_assoc(), whileMYSQLI_NUMwill behave identically to the mysqli_fetch_row() function. The final optionMYSQLI_BOTHwill create a single array with the attributes of both.
Return Values
Returns an array of strings that corresponds to the fetched row or NULL if there
are no more rows in resultset.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if ($mysqli->connect_errno) {
printf("Connect failed: %s\n", $mysqli->connect_error);
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID LIMIT 3";
$result = $mysqli->query($query);
/* numeric array */
$row = $result->fetch_array(MYSQLI_NUM);
printf ("%s (%s)\n", $row[0], $row[1]);
/* associative array */
$row = $result->fetch_array(MYSQLI_ASSOC);
printf ("%s (%s)\n", $row["Name"], $row["CountryCode"]);
/* associative and numeric array */
$row = $result->fetch_array(MYSQLI_BOTH);
printf ("%s (%s)\n", $row[0], $row["CountryCode"]);
/* free result set */
$result->free();
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID LIMIT 3";
$result = mysqli_query($link, $query);
/* numeric array */
$row = mysqli_fetch_array($result, MYSQLI_NUM);
printf ("%s (%s)\n", $row[0], $row[1]);
/* associative array */
$row = mysqli_fetch_array($result, MYSQLI_ASSOC);
printf ("%s (%s)\n", $row["Name"], $row["CountryCode"]);
/* associative and numeric array */
$row = mysqli_fetch_array($result, MYSQLI_BOTH);
printf ("%s (%s)\n", $row[0], $row["CountryCode"]);
/* free result set */
mysqli_free_result($result);
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Kabul (AFG) Qandahar (AFG) Herat (AFG)
See Also
- mysqli_fetch_assoc() - Fetch a result row as an associative array
- mysqli_fetch_row() - Get a result row as an enumerated array
- mysqli_fetch_object() - Returns the current row of a result set as an object
- mysqli_query() - Performs a query on the database
- mysqli_data_seek() - Adjusts the result pointer to an arbitrary row in the result
mysqli_result::fetch_assoc
mysqli_fetch_assoc
(PHP 5, PHP 7)
mysqli_result::fetch_assoc -- mysqli_fetch_assoc — Fetch a result row as an associative array
Description
Object oriented style
Procedural style
Returns an associative array that corresponds to the fetched row or NULL
if there are no more rows.
Note: Field names returned by this function are case-sensitive.
Note: This function sets NULL fields to the PHP
NULLvalue.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
Return Values
Returns an associative array of strings representing the fetched row in the result
set, where each key in the array represents the name of one of the result
set's columns or NULL if there are no more rows in resultset.
If two or more columns of the result have the same field names, the last column will take precedence. To access the other column(s) of the same name, you either need to access the result with numeric indices by using mysqli_fetch_row() or add alias names.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if ($mysqli->connect_errno) {
printf("Connect failed: %s\n", $mysqli->connect_error);
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";
if ($result = $mysqli->query($query)) {
/* fetch associative array */
while ($row = $result->fetch_assoc()) {
printf ("%s (%s)\n", $row["Name"], $row["CountryCode"]);
}
/* free result set */
$result->free();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";
if ($result = mysqli_query($link, $query)) {
/* fetch associative array */
while ($row = mysqli_fetch_assoc($result)) {
printf ("%s (%s)\n", $row["Name"], $row["CountryCode"]);
}
/* free result set */
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Pueblo (USA) Arvada (USA) Cape Coral (USA) Green Bay (USA) Santa Clara (USA)
Example #3 A mysqli_result example comparing iterator usage
<?php
$c = mysqli_connect('127.0.0.1','user', 'pass');
// Using iterators (support was added with PHP 5.4)
foreach ( $c->query('SELECT user,host FROM mysql.user') as $row ) {
printf("'%s'@'%s'\n", $row['user'], $row['host']);
}
echo "\n==================\n";
// Not using iterators
$result = $c->query('SELECT user,host FROM mysql.user');
while ($row = $result->fetch_assoc()) {
printf("'%s'@'%s'\n", $row['user'], $row['host']);
}
?>
The above example will output something similar to:
'root'@'192.168.1.1' 'root'@'127.0.0.1' 'dude'@'localhost' 'lebowski'@'localhost' ================== 'root'@'192.168.1.1' 'root'@'127.0.0.1' 'dude'@'localhost' 'lebowski'@'localhost'
See Also
- mysqli_fetch_array() - Fetch a result row as an associative, a numeric array, or both
- mysqli_fetch_row() - Get a result row as an enumerated array
- mysqli_fetch_object() - Returns the current row of a result set as an object
- mysqli_query() - Performs a query on the database
- mysqli_data_seek() - Adjusts the result pointer to an arbitrary row in the result
mysqli_result::fetch_field_direct
mysqli_fetch_field_direct
(PHP 5, PHP 7)
mysqli_result::fetch_field_direct -- mysqli_fetch_field_direct — Fetch meta-data for a single field
Description
Object oriented style
$fieldnr
) : objectProcedural style
Returns an object which contains field definition information from the specified result set.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
-
fieldnr -
The field number. This value must be in the range from
0tonumber of fields - 1.
Return Values
Returns an object which contains field definition information or FALSE
if no field information for specified fieldnr is
available.
| Attribute | Description |
|---|---|
| name | The name of the column |
| orgname | Original column name if an alias was specified |
| table | The name of the table this field belongs to (if not calculated) |
| orgtable | Original table name if an alias was specified |
| def | The default value for this field, represented as a string |
| max_length | The maximum width of the field for the result set. |
| length | The width of the field, as specified in the table definition. |
| charsetnr | The character set number for the field. |
| flags | An integer representing the bit-flags for the field. |
| type | The data type used for this field |
| decimals | The number of decimals used (for numeric fields) |
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, SurfaceArea from Country ORDER BY Name LIMIT 5";
if ($result = $mysqli->query($query)) {
/* Get field information for column 'SurfaceArea' */
$finfo = $result->fetch_field_direct(1);
printf("Name: %s\n", $finfo->name);
printf("Table: %s\n", $finfo->table);
printf("max. Len: %d\n", $finfo->max_length);
printf("Flags: %d\n", $finfo->flags);
printf("Type: %d\n", $finfo->type);
$result->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, SurfaceArea from Country ORDER BY Name LIMIT 5";
if ($result = mysqli_query($link, $query)) {
/* Get field information for column 'SurfaceArea' */
$finfo = mysqli_fetch_field_direct($result, 1);
printf("Name: %s\n", $finfo->name);
printf("Table: %s\n", $finfo->table);
printf("max. Len: %d\n", $finfo->max_length);
printf("Flags: %d\n", $finfo->flags);
printf("Type: %d\n", $finfo->type);
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Name: SurfaceArea Table: Country max. Len: 10 Flags: 32769 Type: 4
See Also
- mysqli_num_fields() - Get the number of fields in a result
- mysqli_fetch_field() - Returns the next field in the result set
- mysqli_fetch_fields() - Returns an array of objects representing the fields in a result set
mysqli_result::fetch_field
mysqli_fetch_field
(PHP 5, PHP 7)
mysqli_result::fetch_field -- mysqli_fetch_field — Returns the next field in the result set
Description
Object oriented style
Procedural style
Returns the definition of one column of a result set as an object. Call this function repeatedly to retrieve information about all columns in the result set.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
Return Values
Returns an object which contains field definition information or FALSE
if no field information is available.
| Property | Description |
|---|---|
| name | The name of the column |
| orgname | Original column name if an alias was specified |
| table | The name of the table this field belongs to (if not calculated) |
| orgtable | Original table name if an alias was specified |
| def | Reserved for default value, currently always "" |
| db | Database (since PHP 5.3.6) |
| catalog | The catalog name, always "def" (since PHP 5.3.6) |
| max_length | The maximum width of the field for the result set. |
| length | The width of the field, as specified in the table definition. |
| charsetnr | The character set number for the field. |
| flags | An integer representing the bit-flags for the field. |
| type | The data type used for this field |
| decimals | The number of decimals used (for integer fields) |
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5";
if ($result = $mysqli->query($query)) {
/* Get field information for all columns */
while ($finfo = $result->fetch_field()) {
printf("Name: %s\n", $finfo->name);
printf("Table: %s\n", $finfo->table);
printf("max. Len: %d\n", $finfo->max_length);
printf("Flags: %d\n", $finfo->flags);
printf("Type: %d\n\n", $finfo->type);
}
$result->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5";
if ($result = mysqli_query($link, $query)) {
/* Get field information for all fields */
while ($finfo = mysqli_fetch_field($result)) {
printf("Name: %s\n", $finfo->name);
printf("Table: %s\n", $finfo->table);
printf("max. Len: %d\n", $finfo->max_length);
printf("Flags: %d\n", $finfo->flags);
printf("Type: %d\n\n", $finfo->type);
}
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Name: Name Table: Country max. Len: 11 Flags: 1 Type: 254 Name: SurfaceArea Table: Country max. Len: 10 Flags: 32769 Type: 4
See Also
- mysqli_num_fields() - Get the number of fields in a result
- mysqli_fetch_field_direct() - Fetch meta-data for a single field
- mysqli_fetch_fields() - Returns an array of objects representing the fields in a result set
- mysqli_field_seek() - Set result pointer to a specified field offset
mysqli_result::fetch_fields
mysqli_fetch_fields
(PHP 5, PHP 7)
mysqli_result::fetch_fields -- mysqli_fetch_fields — Returns an array of objects representing the fields in a result set
Description
Object oriented style
Procedural style
This function serves an identical purpose to the mysqli_fetch_field() function with the single difference that, instead of returning one object at a time for each field, the columns are returned as an array of objects.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
Return Values
Returns an array of objects which contains field definition information or
FALSE if no field information is available.
| Property | Description |
|---|---|
| name | The name of the column |
| orgname | Original column name if an alias was specified |
| table | The name of the table this field belongs to (if not calculated) |
| orgtable | Original table name if an alias was specified |
| max_length | The maximum width of the field for the result set. |
| length | The width of the field, in bytes, as specified in the table definition. Note that this number (bytes) might differ from your table definition value (characters), depending on the character set you use. For example, the character set utf8 has 3 bytes per character, so varchar(10) will return a length of 30 for utf8 (10*3), but return 10 for latin1 (10*1). |
| charsetnr | The character set number (id) for the field. |
| flags | An integer representing the bit-flags for the field. |
| type | The data type used for this field |
| decimals | The number of decimals used (for integer fields) |
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("127.0.0.1", "root", "foofoo", "sakila");
/* check connection */
if ($mysqli->connect_errno) {
printf("Connect failed: %s\n", $mysqli->connect_error);
exit();
}
foreach (array('latin1', 'utf8') as $charset) {
// Set character set, to show its impact on some values (e.g., length in bytes)
$mysqli->set_charset($charset);
$query = "SELECT actor_id, last_name from actor ORDER BY actor_id";
echo "======================\n";
echo "Character Set: $charset\n";
echo "======================\n";
if ($result = $mysqli->query($query)) {
/* Get field information for all columns */
$finfo = $result->fetch_fields();
foreach ($finfo as $val) {
printf("Name: %s\n", $val->name);
printf("Table: %s\n", $val->table);
printf("Max. Len: %d\n", $val->max_length);
printf("Length: %d\n", $val->length);
printf("charsetnr: %d\n", $val->charsetnr);
printf("Flags: %d\n", $val->flags);
printf("Type: %d\n\n", $val->type);
}
$result->free();
}
}
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("127.0.0.1", "my_user", "my_password", "sakila");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
foreach (array('latin1', 'utf8') as $charset) {
// Set character set, to show its impact on some values (e.g., length in bytes)
mysqli_set_charset($link, $charset);
$query = "SELECT actor_id, last_name from actor ORDER BY actor_id";
echo "======================\n";
echo "Character Set: $charset\n";
echo "======================\n";
if ($result = mysqli_query($link, $query)) {
/* Get field information for all columns */
$finfo = mysqli_fetch_fields($result);
foreach ($finfo as $val) {
printf("Name: %s\n", $val->name);
printf("Table: %s\n", $val->table);
printf("Max. Len: %d\n", $val->max_length);
printf("Length: %d\n", $val->length);
printf("charsetnr: %d\n", $val->charsetnr);
printf("Flags: %d\n", $val->flags);
printf("Type: %d\n\n", $val->type);
}
mysqli_free_result($result);
}
}
mysqli_close($link);
?>
The above examples will output:
====================== Character Set: latin1 ====================== Name: actor_id Table: actor Max. Len: 3 Length: 5 charsetnr: 63 Flags: 49699 Type: 2 Name: last_name Table: actor Max. Len: 12 Length: 45 charsetnr: 8 Flags: 20489 Type: 253 ====================== Character Set: utf8 ====================== Name: actor_id Table: actor Max. Len: 3 Length: 5 charsetnr: 63 Flags: 49699 Type: 2 Name: last_name Table: actor Max. Len: 12 Length: 135 charsetnr: 33 Flags: 20489
See Also
- mysqli_num_fields() - Get the number of fields in a result
- mysqli_fetch_field_direct() - Fetch meta-data for a single field
- mysqli_fetch_field() - Returns the next field in the result set
mysqli_result::fetch_object
mysqli_fetch_object
(PHP 5, PHP 7)
mysqli_result::fetch_object -- mysqli_fetch_object — Returns the current row of a result set as an object
Description
Object oriented style
$class_name = "stdClass"
[, array $params
]] ) : objectProcedural style
$result
[, string $class_name = "stdClass"
[, array $params
]] ) : objectThe mysqli_fetch_object() will return the current row result set as an object where the attributes of the object represent the names of the fields found within the result set.
Note that mysqli_fetch_object() sets the properties of the object before calling the object constructor.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
-
class_name -
The name of the class to instantiate, set the properties of and return. If not specified, a stdClass object is returned.
-
params -
An optional array of parameters to pass to the constructor for
class_nameobjects.
Return Values
Returns an object with string properties that corresponds to the fetched
row or NULL if there are no more rows in resultset.
Note: Field names returned by this function are case-sensitive.
Note: This function sets NULL fields to the PHP
NULLvalue.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";
if ($result = $mysqli->query($query)) {
/* fetch object array */
while ($obj = $result->fetch_object()) {
printf ("%s (%s)\n", $obj->Name, $obj->CountryCode);
}
/* free result set */
$result->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";
if ($result = mysqli_query($link, $query)) {
/* fetch associative array */
while ($obj = mysqli_fetch_object($result)) {
printf ("%s (%s)\n", $obj->Name, $obj->CountryCode);
}
/* free result set */
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Pueblo (USA) Arvada (USA) Cape Coral (USA) Green Bay (USA) Santa Clara (USA)
See Also
- mysqli_fetch_array() - Fetch a result row as an associative, a numeric array, or both
- mysqli_fetch_assoc() - Fetch a result row as an associative array
- mysqli_fetch_row() - Get a result row as an enumerated array
- mysqli_query() - Performs a query on the database
- mysqli_data_seek() - Adjusts the result pointer to an arbitrary row in the result
mysqli_result::fetch_row
mysqli_fetch_row
(PHP 5, PHP 7)
mysqli_result::fetch_row -- mysqli_fetch_row — Get a result row as an enumerated array
Description
Object oriented style
Procedural style
Fetches one row of data from the result set and returns it as an enumerated
array, where each column is stored in an array offset starting from 0 (zero).
Each subsequent call to this function will return the next row within the
result set, or NULL if there are no more rows.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
Return Values
mysqli_fetch_row() returns an array of strings that corresponds to the fetched row
or NULL if there are no more rows in result set.
Note: This function sets NULL fields to the PHP
NULLvalue.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";
if ($result = $mysqli->query($query)) {
/* fetch object array */
while ($row = $result->fetch_row()) {
printf ("%s (%s)\n", $row[0], $row[1]);
}
/* free result set */
$result->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";
if ($result = mysqli_query($link, $query)) {
/* fetch associative array */
while ($row = mysqli_fetch_row($result)) {
printf ("%s (%s)\n", $row[0], $row[1]);
}
/* free result set */
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Pueblo (USA) Arvada (USA) Cape Coral (USA) Green Bay (USA) Santa Clara (USA)
See Also
- mysqli_fetch_array() - Fetch a result row as an associative, a numeric array, or both
- mysqli_fetch_assoc() - Fetch a result row as an associative array
- mysqli_fetch_object() - Returns the current row of a result set as an object
- mysqli_query() - Performs a query on the database
- mysqli_data_seek() - Adjusts the result pointer to an arbitrary row in the result
mysqli_result::$field_count
mysqli_num_fields
(PHP 5, PHP 7)
mysqli_result::$field_count -- mysqli_num_fields — Get the number of fields in a result
Description
Object oriented style
Procedural style
Returns the number of fields from specified result set.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
Return Values
The number of fields from a result set.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if ($result = $mysqli->query("SELECT * FROM City ORDER BY ID LIMIT 1")) {
/* determine number of fields in result set */
$field_cnt = $result->field_count;
printf("Result set has %d fields.\n", $field_cnt);
/* close result set */
$result->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if ($result = mysqli_query($link, "SELECT * FROM City ORDER BY ID LIMIT 1")) {
/* determine number of fields in result set */
$field_cnt = mysqli_num_fields($result);
printf("Result set has %d fields.\n", $field_cnt);
/* close result set */
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Result set has 5 fields.
mysqli_result::field_seek
mysqli_field_seek
(PHP 5, PHP 7)
mysqli_result::field_seek -- mysqli_field_seek — Set result pointer to a specified field offset
Description
Object oriented style
$fieldnr
) : boolProcedural style
Sets the field cursor to the given offset. The next call to mysqli_fetch_field() will retrieve the field definition of the column associated with that offset.
Note:
To seek to the beginning of a row, pass an offset value of zero.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
-
fieldnr -
The field number. This value must be in the range from
0tonumber of fields - 1.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5";
if ($result = $mysqli->query($query)) {
/* Get field information for 2nd column */
$result->field_seek(1);
$finfo = $result->fetch_field();
printf("Name: %s\n", $finfo->name);
printf("Table: %s\n", $finfo->table);
printf("max. Len: %d\n", $finfo->max_length);
printf("Flags: %d\n", $finfo->flags);
printf("Type: %d\n\n", $finfo->type);
$result->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5";
if ($result = mysqli_query($link, $query)) {
/* Get field information for 2nd column */
mysqli_field_seek($result, 1);
$finfo = mysqli_fetch_field($result);
printf("Name: %s\n", $finfo->name);
printf("Table: %s\n", $finfo->table);
printf("max. Len: %d\n", $finfo->max_length);
printf("Flags: %d\n", $finfo->flags);
printf("Type: %d\n\n", $finfo->type);
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Name: SurfaceArea Table: Country max. Len: 10 Flags: 32769 Type: 4
mysqli_result::free
mysqli_result::close
mysqli_result::free_result
mysqli_free_result
(PHP 5, PHP 7)
mysqli_result::free -- mysqli_result::close -- mysqli_result::free_result -- mysqli_free_result — Frees the memory associated with a result
Description
Object oriented style
Procedural style
Frees the memory associated with the result.
Note:
You should always free your result with mysqli_free_result(), when your result object is not needed anymore.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
Return Values
No value is returned.
See Also
- mysqli_query() - Performs a query on the database
- mysqli_stmt_store_result() - Transfers a result set from a prepared statement
- mysqli_store_result() - Transfers a result set from the last query
- mysqli_use_result() - Initiate a result set retrieval
mysqli_result::$lengths
mysqli_fetch_lengths
(PHP 5, PHP 7)
mysqli_result::$lengths -- mysqli_fetch_lengths — Returns the lengths of the columns of the current row in the result set
Description
Object oriented style
Procedural style
The mysqli_fetch_lengths() function returns an array containing the lengths of every column of the current row within the result set.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
Return Values
An array of integers representing the size of each column (not including
any terminating null characters). FALSE if an error occurred.
mysqli_fetch_lengths() is valid only for the current
row of the result set. It returns FALSE if you call it before calling
mysqli_fetch_row/array/object or after retrieving all rows in the result.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT * from Country ORDER BY Code LIMIT 1";
if ($result = $mysqli->query($query)) {
$row = $result->fetch_row();
/* display column lengths */
foreach ($result->lengths as $i => $val) {
printf("Field %2d has Length %2d\n", $i+1, $val);
}
$result->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT * from Country ORDER BY Code LIMIT 1";
if ($result = mysqli_query($link, $query)) {
$row = mysqli_fetch_row($result);
/* display column lengths */
foreach (mysqli_fetch_lengths($result) as $i => $val) {
printf("Field %2d has Length %2d\n", $i+1, $val);
}
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Field 1 has Length 3 Field 2 has Length 5 Field 3 has Length 13 Field 4 has Length 9 Field 5 has Length 6 Field 6 has Length 1 Field 7 has Length 6 Field 8 has Length 4 Field 9 has Length 6 Field 10 has Length 6 Field 11 has Length 5 Field 12 has Length 44 Field 13 has Length 7 Field 14 has Length 3 Field 15 has Length 2
mysqli_result::$num_rows
mysqli_num_rows
(PHP 5, PHP 7)
mysqli_result::$num_rows -- mysqli_num_rows — Gets the number of rows in a result
Description
Object oriented style
Procedural style
Returns the number of rows in the result set.
The behaviour of mysqli_num_rows() depends on whether buffered or unbuffered result sets are being used. For unbuffered result sets, mysqli_num_rows() will not return the correct number of rows until all the rows in the result have been retrieved.
Parameters
-
result -
Procedural style only: A result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result().
Return Values
Returns number of rows in the result set.
Note:
If the number of rows is greater than
PHP_INT_MAX, the number will be returned as a string.
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if ($result = $mysqli->query("SELECT Code, Name FROM Country ORDER BY Name")) {
/* determine number of rows result set */
$row_cnt = $result->num_rows;
printf("Result set has %d rows.\n", $row_cnt);
/* close result set */
$result->close();
}
/* close connection */
$mysqli->close();
?>
Example #2 Procedural style
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
if ($result = mysqli_query($link, "SELECT Code, Name FROM Country ORDER BY Name")) {
/* determine number of rows result set */
$row_cnt = mysqli_num_rows($result);
printf("Result set has %d rows.\n", $row_cnt);
/* close result set */
mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
The above examples will output:
Result set has 239 rows.
See Also
- mysqli_affected_rows() - Gets the number of affected rows in a previous MySQL operation
- mysqli_store_result() - Transfers a result set from the last query
- mysqli_use_result() - Initiate a result set retrieval
- mysqli_query() - Performs a query on the database
Table of Contents
- mysqli_result::$current_field — Get current field offset of a result pointer
- mysqli_result::data_seek — Adjusts the result pointer to an arbitrary row in the result
- mysqli_result::fetch_all — Fetches all result rows as an associative array, a numeric array, or both
- mysqli_result::fetch_array — Fetch a result row as an associative, a numeric array, or both
- mysqli_result::fetch_assoc — Fetch a result row as an associative array
- mysqli_result::fetch_field_direct — Fetch meta-data for a single field
- mysqli_result::fetch_field — Returns the next field in the result set
- mysqli_result::fetch_fields — Returns an array of objects representing the fields in a result set
- mysqli_result::fetch_object — Returns the current row of a result set as an object
- mysqli_result::fetch_row — Get a result row as an enumerated array
- mysqli_result::$field_count — Get the number of fields in a result
- mysqli_result::field_seek — Set result pointer to a specified field offset
- mysqli_result::free — Frees the memory associated with a result
- mysqli_result::$lengths — Returns the lengths of the columns of the current row in the result set
- mysqli_result::$num_rows — Gets the number of rows in a result
The mysqli_driver class
(PHP 5, PHP 7)
Introduction
The mysqli_driver class is an instance of the monostate pattern, i.e. there is only one driver which can be accessed though an arbitrary amount of mysqli_driver instances.
Class synopsis
Properties
- client_info
-
The Client API header version
- client_version
-
The Client version
- driver_version
-
The MySQLi Driver version
- embedded
-
Whether MySQLi Embedded support is enabled
- reconnect
-
Allow or prevent reconnect (see the mysqli.reconnect INI directive)
- report_mode
-
Set to
MYSQLI_REPORT_OFF,MYSQLI_REPORT_ALLor any combination ofMYSQLI_REPORT_STRICT(throw Exceptions for errors),MYSQLI_REPORT_ERROR(report errors) andMYSQLI_REPORT_INDEX(errors regarding indexes). See also mysqli_report().
mysqli_driver::embedded_server_end
mysqli_embedded_server_end
(PHP 5 >= 5.1.0, PHP 7 < 7.4.0)
mysqli_driver::embedded_server_end -- mysqli_embedded_server_end — Stop embedded server
Description
Object oriented style
Procedural style
This function is currently not documented; only its argument list is available.
mysqli_driver::embedded_server_start
mysqli_embedded_server_start
(PHP 5 >= 5.1.0, PHP 7 < 7.4.0)
mysqli_driver::embedded_server_start -- mysqli_embedded_server_start — Initialize and start embedded server
Description
Object oriented style
$start
, array $arguments
, array $groups
) : boolProcedural style
$start
, array $arguments
, array $groups
) : boolThis function is currently not documented; only its argument list is available.
mysqli_driver::$report_mode
mysqli_report
(PHP 5, PHP 7)
mysqli_driver::$report_mode -- mysqli_report — Enables or disables internal report functions
Description
Object oriented style
Procedural style
A function helpful in improving queries during code development and testing. Depending on the flags, it reports errors from mysqli function calls or queries that don't use an index (or use a bad index).
Parameters
-
flags -
Supported flags Name Description MYSQLI_REPORT_OFFTurns reporting off MYSQLI_REPORT_ERRORReport errors from mysqli function calls MYSQLI_REPORT_STRICTThrow mysqli_sql_exception for errors instead of warnings MYSQLI_REPORT_INDEXReport if no index or bad index was used in a query MYSQLI_REPORT_ALLSet all options (report all)
Return Values
Returns TRUE on success or FALSE on failure.
Changelog
| Version | Description |
|---|---|
| 5.3.4 | Changing the reporting mode is now be per-request, rather than per-process. |
| 5.2.15 | Changing the reporting mode is now be per-request, rather than per-process. |
Examples
Example #1 Object oriented style
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* activate reporting */
$driver = new mysqli_driver();
$driver->report_mode = MYSQLI_REPORT_ALL;
try {
/* this query should report an error */
$result = $mysqli->query("SELECT Name FROM Nonexistingtable WHERE population > 50000");
/* this query should report a bad index */
$result = $mysqli->query("SELECT Name FROM City WHERE population > 50000");
$result->close();
$mysqli->close();
} catch (mysqli_sql_exception $e) {
echo $e->__toString();
}
?>
Example #2 Procedural style
<?php
/* activate reporting */
mysqli_report(MYSQLI_REPORT_ALL);
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* this query should report an error */
$result = mysqli_query("SELECT Name FROM Nonexistingtable WHERE population > 50000");
/* this query should report a bad index */
$result = mysqli_query("SELECT Name FROM City WHERE population > 50000");
mysqli_free_result($result);
mysqli_close($link);
?>
See Also
- mysqli_debug() - Performs debugging operations
- mysqli_dump_debug_info() - Dump debugging information into the log
- mysqli_sql_exception
- set_exception_handler() - Sets a user-defined exception handler function
- error_reporting() - Sets which PHP errors are reported
Table of Contents
- mysqli_driver::embedded_server_end — Stop embedded server
- mysqli_driver::embedded_server_start — Initialize and start embedded server
- mysqli_driver::$report_mode — Enables or disables internal report functions
The mysqli_warning class
(PHP 5, PHP 7)
Introduction
Represents a MySQL warning.
Class synopsis
Properties
- message
-
Message string
- sqlstate
-
SQL state
- errno
-
Error number
mysqli_warning::__construct
(PHP 5, PHP 7)
mysqli_warning::__construct — The __construct purpose
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
mysqli_warning::next
(PHP 5, PHP 7)
mysqli_warning::next — Fetch next warning
Description
Change warning information to the next warning if possible.
Once the warning has been set to the next warning, new values of properties message,
sqlstate and errno of mysqli_warning
are available.
Parameters
This function has no parameters.
Return Values
Returns TRUE if next warning was fetched successfully.
If there are no more warnings, it will return FALSE
Table of Contents
- mysqli_warning::__construct — The __construct purpose
- mysqli_warning::next — Fetch next warning
The mysqli_sql_exception class
(PHP 5, PHP 7)
Introduction
The mysqli exception handling class.
Class synopsis
Properties
- sqlstate
-
The sql state with the error.
Aliases and deprecated Mysqli Functions
Description
This function is an alias of: mysqli_stmt_bind_param().
This function has been DEPRECATED as of PHP 5.3.0 and REMOVED as of PHP 5.4.0.
Description
This function is an alias of: mysqli_stmt_bind_result().
This function has been DEPRECATED as of PHP 5.3.0 and REMOVED as of PHP 5.4.0.
Description
This function is an alias of: mysqli_character_set_name().
This function has been DEPRECATED as of PHP 5.3.0 and REMOVED as of PHP 5.4.0.
See Also
- mysqli_real_escape_string() - Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection
Description
This function is an alias of: mysqli::__construct()
Although the mysqli::__construct() documentation also includes procedural examples that use the mysqli_connect() function, here is a short example:
Examples
Example #1 mysqli_connect() example
<?php
$link = mysqli_connect("127.0.0.1", "my_user", "my_password", "my_db");
if (!$link) {
echo "Error: Unable to connect to MySQL." . PHP_EOL;
echo "Debugging errno: " . mysqli_connect_errno() . PHP_EOL;
echo "Debugging error: " . mysqli_connect_error() . PHP_EOL;
exit;
}
echo "Success: A proper connection to MySQL was made! The my_db database is great." . PHP_EOL;
echo "Host information: " . mysqli_get_host_info($link) . PHP_EOL;
mysqli_close($link);
?>
The above examples will output something similar to:
Success: A proper connection to MySQL was made! The my_db database is great. Host information: localhost via TCP/IP
mysqli::disable_reads_from_master
mysqli_disable_reads_from_master
(PHP 5 < 5.3.0)
mysqli::disable_reads_from_master -- mysqli_disable_reads_from_master — Disable reads from master
Description
Object oriented style
Procedural style
This function is currently not documented; only its argument list is available.
This function has been DEPRECATED and REMOVED as of PHP 5.3.0.
mysqli_disable_rpl_parse
(PHP 5 < 5.3.0)
mysqli_disable_rpl_parse — Disable RPL parse
Description
This function is currently not documented; only its argument list is available.
This function has been DEPRECATED and REMOVED as of PHP 5.3.0.
mysqli_enable_reads_from_master
(PHP 5 < 5.3.0)
mysqli_enable_reads_from_master — Enable reads from master
Description
This function is currently not documented; only its argument list is available.
This function has been DEPRECATED and REMOVED as of PHP 5.3.0.
mysqli_enable_rpl_parse
(PHP 5 < 5.3.0)
mysqli_enable_rpl_parse — Enable RPL parse
Description
This function is currently not documented; only its argument list is available.
This function has been DEPRECATED and REMOVED as of PHP 5.3.0.
Description
This function is an alias of: mysqli_real_escape_string().
Description
This function is an alias of: mysqli_stmt_execute().
Notes
Note:
mysqli_execute() is deprecated and will be removed.
Description
This function is an alias of: mysqli_stmt_fetch().
This function has been DEPRECATED as of PHP 5.3.0 and REMOVED as of PHP 5.4.0.
mysqli_get_cache_stats
(PHP 5 >= 5.3.0 and < 5.4.0)
mysqli_get_cache_stats — Returns client Zval cache statistics
This function has been REMOVED as of PHP 5.4.0.
Description
Returns an empty array. Available only with mysqlnd.
Parameters
Return Values
Returns an empty array on success, FALSE otherwise.
Changelog
| Version | Description |
|---|---|
| 5.4.0 | The mysqli_get_cache_stats() was removed. |
| 5.3.0 | The mysqli_get_cache_stats() was added as stub. |
mysqli_get_client_stats
(PHP 5 >= 5.3.0, PHP 7)
mysqli_get_client_stats — Returns client per-process statistics
Description
Returns client per-process statistics. Available only with mysqlnd.
Parameters
Return Values
Returns an array with client stats if success, FALSE otherwise.
Examples
Example #1 A mysqli_get_client_stats() example
<?php
$link = mysqli_connect();
print_r(mysqli_get_client_stats());
?>
The above example will output something similar to:
Array
(
[bytes_sent] => 43
[bytes_received] => 80
[packets_sent] => 1
[packets_received] => 2
[protocol_overhead_in] => 8
[protocol_overhead_out] => 4
[bytes_received_ok_packet] => 11
[bytes_received_eof_packet] => 0
[bytes_received_rset_header_packet] => 0
[bytes_received_rset_field_meta_packet] => 0
[bytes_received_rset_row_packet] => 0
[bytes_received_prepare_response_packet] => 0
[bytes_received_change_user_packet] => 0
[packets_sent_command] => 0
[packets_received_ok] => 1
[packets_received_eof] => 0
[packets_received_rset_header] => 0
[packets_received_rset_field_meta] => 0
[packets_received_rset_row] => 0
[packets_received_prepare_response] => 0
[packets_received_change_user] => 0
[result_set_queries] => 0
[non_result_set_queries] => 0
[no_index_used] => 0
[bad_index_used] => 0
[slow_queries] => 0
[buffered_sets] => 0
[unbuffered_sets] => 0
[ps_buffered_sets] => 0
[ps_unbuffered_sets] => 0
[flushed_normal_sets] => 0
[flushed_ps_sets] => 0
[ps_prepared_never_executed] => 0
[ps_prepared_once_executed] => 0
[rows_fetched_from_server_normal] => 0
[rows_fetched_from_server_ps] => 0
[rows_buffered_from_client_normal] => 0
[rows_buffered_from_client_ps] => 0
[rows_fetched_from_client_normal_buffered] => 0
[rows_fetched_from_client_normal_unbuffered] => 0
[rows_fetched_from_client_ps_buffered] => 0
[rows_fetched_from_client_ps_unbuffered] => 0
[rows_fetched_from_client_ps_cursor] => 0
[rows_skipped_normal] => 0
[rows_skipped_ps] => 0
[copy_on_write_saved] => 0
[copy_on_write_performed] => 0
[command_buffer_too_small] => 0
[connect_success] => 1
[connect_failure] => 0
[connection_reused] => 0
[reconnect] => 0
[pconnect_success] => 0
[active_connections] => 1
[active_persistent_connections] => 0
[explicit_close] => 0
[implicit_close] => 0
[disconnect_close] => 0
[in_middle_of_command_close] => 0
[explicit_free_result] => 0
[implicit_free_result] => 0
[explicit_stmt_close] => 0
[implicit_stmt_close] => 0
[mem_emalloc_count] => 0
[mem_emalloc_ammount] => 0
[mem_ecalloc_count] => 0
[mem_ecalloc_ammount] => 0
[mem_erealloc_count] => 0
[mem_erealloc_ammount] => 0
[mem_efree_count] => 0
[mem_malloc_count] => 0
[mem_malloc_ammount] => 0
[mem_calloc_count] => 0
[mem_calloc_ammount] => 0
[mem_realloc_count] => 0
[mem_realloc_ammount] => 0
[mem_free_count] => 0
[proto_text_fetched_null] => 0
[proto_text_fetched_bit] => 0
[proto_text_fetched_tinyint] => 0
[proto_text_fetched_short] => 0
[proto_text_fetched_int24] => 0
[proto_text_fetched_int] => 0
[proto_text_fetched_bigint] => 0
[proto_text_fetched_decimal] => 0
[proto_text_fetched_float] => 0
[proto_text_fetched_double] => 0
[proto_text_fetched_date] => 0
[proto_text_fetched_year] => 0
[proto_text_fetched_time] => 0
[proto_text_fetched_datetime] => 0
[proto_text_fetched_timestamp] => 0
[proto_text_fetched_string] => 0
[proto_text_fetched_blob] => 0
[proto_text_fetched_enum] => 0
[proto_text_fetched_set] => 0
[proto_text_fetched_geometry] => 0
[proto_text_fetched_other] => 0
[proto_binary_fetched_null] => 0
[proto_binary_fetched_bit] => 0
[proto_binary_fetched_tinyint] => 0
[proto_binary_fetched_short] => 0
[proto_binary_fetched_int24] => 0
[proto_binary_fetched_int] => 0
[proto_binary_fetched_bigint] => 0
[proto_binary_fetched_decimal] => 0
[proto_binary_fetched_float] => 0
[proto_binary_fetched_double] => 0
[proto_binary_fetched_date] => 0
[proto_binary_fetched_year] => 0
[proto_binary_fetched_time] => 0
[proto_binary_fetched_datetime] => 0
[proto_binary_fetched_timestamp] => 0
[proto_binary_fetched_string] => 0
[proto_binary_fetched_blob] => 0
[proto_binary_fetched_enum] => 0
[proto_binary_fetched_set] => 0
[proto_binary_fetched_geometry] => 0
[proto_binary_fetched_other] => 0
)
mysqli_get_links_stats
(PHP 5 >= 5.6.0, PHP 7)
mysqli_get_links_stats — Return information about open and cached links
Description
mysqli_get_links_stats() returns information about open and cached MySQL links.
Parameters
This function has no parameters.
Return Values
mysqli_get_links_stats() returns an associative array with three elements, keyed as follows:
Description
This function is an alias of: mysqli_stmt_result_metadata().
This function has been DEPRECATED as of PHP 5.3.0 and REMOVED as of PHP 5.4.0.
mysqli_master_query
(PHP 5 < 5.3.0)
mysqli_master_query — Enforce execution of a query on the master in a master/slave setup
Description
This function is currently not documented; only its argument list is available.
This function has been DEPRECATED and REMOVED as of PHP 5.3.0.
Description
This function is an alias of: mysqli_stmt_param_count().
This function has been DEPRECATED as of PHP 5.3.0 and REMOVED as of PHP 5.4.0.
Description
This function is an alias of: mysqli_driver->report_mode
mysqli_rpl_parse_enabled
(PHP 5 < 5.3.0)
mysqli_rpl_parse_enabled — Check if RPL parse is enabled
Description
This function is currently not documented; only its argument list is available.
This function has been DEPRECATED and REMOVED as of PHP 5.3.0.
mysqli_rpl_probe
(PHP 5 < 5.3.0)
mysqli_rpl_probe — RPL probe
Description
This function is currently not documented; only its argument list is available.
This function has been DEPRECATED and REMOVED as of PHP 5.3.0.
Description
This function is an alias of: mysqli_stmt_send_long_data().
This function has been DEPRECATED as of PHP 5.3.0 and REMOVED as of PHP 5.4.0.
mysqli::set_opt
mysqli_set_opt
(PHP 5, PHP 7)
mysqli::set_opt -- mysqli_set_opt — Alias of mysqli_options()
Description
This function is an alias of: mysqli_options().
mysqli_slave_query
(PHP 5 < 5.3.0)
mysqli_slave_query — Force execution of a query on a slave in a master/slave setup
Description
This function is currently not documented; only its argument list is available.
This function has been DEPRECATED and REMOVED as of PHP 5.3.0.
Table of Contents
- mysqli_bind_param — Alias for mysqli_stmt_bind_param
- mysqli_bind_result — Alias for mysqli_stmt_bind_result
- mysqli_client_encoding — Alias of mysqli_character_set_name
- mysqli_connect — Alias of mysqli::__construct
- mysqli::disable_reads_from_master — Disable reads from master
- mysqli_disable_rpl_parse — Disable RPL parse
- mysqli_enable_reads_from_master — Enable reads from master
- mysqli_enable_rpl_parse — Enable RPL parse
- mysqli_escape_string — Alias of mysqli_real_escape_string
- mysqli_execute — Alias for mysqli_stmt_execute
- mysqli_fetch — Alias for mysqli_stmt_fetch
- mysqli_get_cache_stats — Returns client Zval cache statistics
- mysqli_get_client_stats — Returns client per-process statistics
- mysqli_get_links_stats — Return information about open and cached links
- mysqli_get_metadata — Alias for mysqli_stmt_result_metadata
- mysqli_master_query — Enforce execution of a query on the master in a master/slave setup
- mysqli_param_count — Alias for mysqli_stmt_param_count
- mysqli_report — Alias of mysqli_driver->report_mode
- mysqli_rpl_parse_enabled — Check if RPL parse is enabled
- mysqli_rpl_probe — RPL probe
- mysqli_send_long_data — Alias for mysqli_stmt_send_long_data
- mysqli::set_opt — Alias of mysqli_options
- mysqli_slave_query — Force execution of a query on a slave in a master/slave setup
Changelog
The following changes have been made to classes/functions/methods of this extension.
| Version | Function | Description |
|---|---|---|
| 5.6.16 | mysqli::real_connect | Added the MYSQLI_CLIENT_SSL_DONT_VERIFY_SERVER_CERT flag for MySQL Native Driver |
| 5.5.0 | mysqli::commit | Added flags and name parameters. |
| mysqli::options | The MYSQLI_SERVER_PUBLIC_KEY option was added. | |
| mysqli::rollback | Added flags and name parameters. | |
| 5.4.0 | mysqli_get_cache_stats | The mysqli_get_cache_stats was removed. |
| 5.3.4 | mysqli_driver::$report_mode | Changing the reporting mode is now be per-request, rather than per-process. |
| 5.3.0 | mysqli_get_cache_stats | The mysqli_get_cache_stats was added as stub. |
| mysqli::__construct | Added the ability of persistent connections. | |
| mysqli::options | The MYSQLI_OPT_INT_AND_FLOAT_NATIVE, MYSQLI_OPT_NET_CMD_BUFFER_SIZE, MYSQLI_OPT_NET_READ_BUFFER_SIZE, and MYSQLI_OPT_SSL_VERIFY_SERVER_CERT options were added. | |
| mysqli::query | Added the ability of async queries. | |
| 5.2.15 | mysqli_driver::$report_mode | Changing the reporting mode is now be per-request, rather than per-process. |
- Introduction
- Overview
- Quick start guide
- Installing/Configuring
- The mysqli Extension and Persistent Connections
- Predefined Constants
- Notes
- The MySQLi Extension Function Summary
- Examples
- mysqli — The mysqli class
- mysqli::$affected_rows — Gets the number of affected rows in a previous MySQL operation
- mysqli::autocommit — Turns on or off auto-committing database modifications
- mysqli::begin_transaction — Starts a transaction
- mysqli::change_user — Changes the user of the specified database connection
- mysqli::character_set_name — Returns the default character set for the database connection
- mysqli::close — Closes a previously opened database connection
- mysqli::commit — Commits the current transaction
- mysqli::$connect_errno — Returns the error code from last connect call
- mysqli::$connect_error — Returns a string description of the last connect error
- mysqli::__construct — Open a new connection to the MySQL server
- mysqli::debug — Performs debugging operations
- mysqli::dump_debug_info — Dump debugging information into the log
- mysqli::$errno — Returns the error code for the most recent function call
- mysqli::$error_list — Returns a list of errors from the last command executed
- mysqli::$error — Returns a string description of the last error
- mysqli::$field_count — Returns the number of columns for the most recent query
- mysqli::get_charset — Returns a character set object
- mysqli::$client_info — Get MySQL client info
- mysqli::$client_version — Returns the MySQL client version as an integer
- mysqli::get_connection_stats — Returns statistics about the client connection
- mysqli::$host_info — Returns a string representing the type of connection used
- mysqli::$protocol_version — Returns the version of the MySQL protocol used
- mysqli::$server_info — Returns the version of the MySQL server
- mysqli::$server_version — Returns the version of the MySQL server as an integer
- mysqli::get_warnings — Get result of SHOW WARNINGS
- mysqli::$info — Retrieves information about the most recently executed query
- mysqli::init — Initializes MySQLi and returns a resource for use with mysqli_real_connect()
- mysqli::$insert_id — Returns the auto generated id used in the latest query
- mysqli::kill — Asks the server to kill a MySQL thread
- mysqli::more_results — Check if there are any more query results from a multi query
- mysqli::multi_query — Performs a query on the database
- mysqli::next_result — Prepare next result from multi_query
- mysqli::options — Set options
- mysqli::ping — Pings a server connection, or tries to reconnect if the connection has gone down
- mysqli::poll — Poll connections
- mysqli::prepare — Prepare an SQL statement for execution
- mysqli::query — Performs a query on the database
- mysqli::real_connect — Opens a connection to a mysql server
- mysqli::real_escape_string — Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection
- mysqli::real_query — Execute an SQL query
- mysqli::reap_async_query — Get result from async query
- mysqli::refresh — Refreshes
- mysqli::release_savepoint — Removes the named savepoint from the set of savepoints of the current transaction
- mysqli::rollback — Rolls back current transaction
- mysqli::rpl_query_type — Returns RPL query type
- mysqli::savepoint — Set a named transaction savepoint
- mysqli::select_db — Selects the default database for database queries
- mysqli::send_query — Send the query and return
- mysqli::set_charset — Sets the default client character set
- mysqli::set_local_infile_default — Unsets user defined handler for load local infile command
- mysqli::set_local_infile_handler — Set callback function for LOAD DATA LOCAL INFILE command
- mysqli::$sqlstate — Returns the SQLSTATE error from previous MySQL operation
- mysqli::ssl_set — Used for establishing secure connections using SSL
- mysqli::stat — Gets the current system status
- mysqli::stmt_init — Initializes a statement and returns an object for use with mysqli_stmt_prepare
- mysqli::store_result — Transfers a result set from the last query
- mysqli::$thread_id — Returns the thread ID for the current connection
- mysqli::thread_safe — Returns whether thread safety is given or not
- mysqli::use_result — Initiate a result set retrieval
- mysqli::$warning_count — Returns the number of warnings from the last query for the given link
- mysqli_stmt — The mysqli_stmt class
- mysqli_stmt::$affected_rows — Returns the total number of rows changed, deleted, or inserted by the last executed statement
- mysqli_stmt::attr_get — Used to get the current value of a statement attribute
- mysqli_stmt::attr_set — Used to modify the behavior of a prepared statement
- mysqli_stmt::bind_param — Binds variables to a prepared statement as parameters
- mysqli_stmt::bind_result — Binds variables to a prepared statement for result storage
- mysqli_stmt::close — Closes a prepared statement
- mysqli_stmt::__construct — Constructs a new mysqli_stmt object
- mysqli_stmt::data_seek — Seeks to an arbitrary row in statement result set
- mysqli_stmt::$errno — Returns the error code for the most recent statement call
- mysqli_stmt::$error_list — Returns a list of errors from the last statement executed
- mysqli_stmt::$error — Returns a string description for last statement error
- mysqli_stmt::execute — Executes a prepared Query
- mysqli_stmt::fetch — Fetch results from a prepared statement into the bound variables
- mysqli_stmt::$field_count — Returns the number of field in the given statement
- mysqli_stmt::free_result — Frees stored result memory for the given statement handle
- mysqli_stmt::get_result — Gets a result set from a prepared statement
- mysqli_stmt::get_warnings — Get result of SHOW WARNINGS
- mysqli_stmt::$insert_id — Get the ID generated from the previous INSERT operation
- mysqli_stmt::more_results — Check if there are more query results from a multiple query
- mysqli_stmt::next_result — Reads the next result from a multiple query
- mysqli_stmt::$num_rows — Return the number of rows in statements result set
- mysqli_stmt::$param_count — Returns the number of parameter for the given statement
- mysqli_stmt::prepare — Prepare an SQL statement for execution
- mysqli_stmt::reset — Resets a prepared statement
- mysqli_stmt::result_metadata — Returns result set metadata from a prepared statement
- mysqli_stmt::send_long_data — Send data in blocks
- mysqli_stmt::$sqlstate — Returns SQLSTATE error from previous statement operation
- mysqli_stmt::store_result — Transfers a result set from a prepared statement
- mysqli_result — The mysqli_result class
- mysqli_result::$current_field — Get current field offset of a result pointer
- mysqli_result::data_seek — Adjusts the result pointer to an arbitrary row in the result
- mysqli_result::fetch_all — Fetches all result rows as an associative array, a numeric array, or both
- mysqli_result::fetch_array — Fetch a result row as an associative, a numeric array, or both
- mysqli_result::fetch_assoc — Fetch a result row as an associative array
- mysqli_result::fetch_field_direct — Fetch meta-data for a single field
- mysqli_result::fetch_field — Returns the next field in the result set
- mysqli_result::fetch_fields — Returns an array of objects representing the fields in a result set
- mysqli_result::fetch_object — Returns the current row of a result set as an object
- mysqli_result::fetch_row — Get a result row as an enumerated array
- mysqli_result::$field_count — Get the number of fields in a result
- mysqli_result::field_seek — Set result pointer to a specified field offset
- mysqli_result::free — Frees the memory associated with a result
- mysqli_result::$lengths — Returns the lengths of the columns of the current row in the result set
- mysqli_result::$num_rows — Gets the number of rows in a result
- mysqli_driver — The mysqli_driver class
- mysqli_driver::embedded_server_end — Stop embedded server
- mysqli_driver::embedded_server_start — Initialize and start embedded server
- mysqli_driver::$report_mode — Enables or disables internal report functions
- mysqli_warning — The mysqli_warning class
- mysqli_warning::__construct — The __construct purpose
- mysqli_warning::next — Fetch next warning
- mysqli_sql_exception — The mysqli_sql_exception class
- Aliases and deprecated Mysqli Functions
- mysqli_bind_param — Alias for mysqli_stmt_bind_param
- mysqli_bind_result — Alias for mysqli_stmt_bind_result
- mysqli_client_encoding — Alias of mysqli_character_set_name
- mysqli_connect — Alias of mysqli::__construct
- mysqli::disable_reads_from_master — Disable reads from master
- mysqli_disable_rpl_parse — Disable RPL parse
- mysqli_enable_reads_from_master — Enable reads from master
- mysqli_enable_rpl_parse — Enable RPL parse
- mysqli_escape_string — Alias of mysqli_real_escape_string
- mysqli_execute — Alias for mysqli_stmt_execute
- mysqli_fetch — Alias for mysqli_stmt_fetch
- mysqli_get_cache_stats — Returns client Zval cache statistics
- mysqli_get_client_stats — Returns client per-process statistics
- mysqli_get_links_stats — Return information about open and cached links
- mysqli_get_metadata — Alias for mysqli_stmt_result_metadata
- mysqli_master_query — Enforce execution of a query on the master in a master/slave setup
- mysqli_param_count — Alias for mysqli_stmt_param_count
- mysqli_report — Alias of mysqli_driver->report_mode
- mysqli_rpl_parse_enabled — Check if RPL parse is enabled
- mysqli_rpl_probe — RPL probe
- mysqli_send_long_data — Alias for mysqli_stmt_send_long_data
- mysqli::set_opt — Alias of mysqli_options
- mysqli_slave_query — Force execution of a query on a slave in a master/slave setup
- Changelog
Mysql_xdevapi
Introduction
This extension provides access to the MySQL Document Store via the X DevAPI. The X DevAPI is a common API provided by multiple MySQL Connectors providing easy access to relational tables as well as collections of documents, which are represented in JSON, from a API with CRUD-style operations.
The X DevAPI uses the X Protocol, the new generation client-server protocol of the MySQL 8.0 server.
For general information about the MySQL Document Store, please refer to the » MySQL Document Store chapter in the MySQL manual.
Installing/Configuring
Table of Contents
Requirements
This extension requires a MySQL 8+ server with the X plugin enabled (default).
Prerequisite libraries for compiling this extension are: Boost (1.53.0 or higher), OpenSSL, and Protobuf.
Installation
This » PECL extension is not bundled with PHP.
An example installation procedure on Ubuntu 18.04 with PHP 7.2:
// Dependencies $ apt install build-essential libprotobuf-dev libboost-dev openssl protobuf-compiler liblz4-tool zstd // PHP with the desired extensions; php7.2-dev is required to compile $ apt install php7.2-cli php7.2-dev php7.2-mysql php7.2-pdo php7.2-xml // Compile the extension $ pecl install mysql_xdevapi
The pecl install command does not enable PHP extensions (by default)
and enabling PHP extensions can be done in several ways.
Another PHP 7.2 on Ubuntu 18.04 example:
// Create its own ini file $ echo "extension=mysql_xdevapi.so" > /etc/php/7.2/mods-available/mysql_xdevapi.ini // Use the 'phpenmod' command (note: it's Debian/Ubuntu specific) $ phpenmod -v 7.2 -s ALL mysql_xdevapi // A 'phpenmod' alternative is to manually symlink it // $ ln -s /etc/php/7.2/mods-available/mysql_xdevapi.ini /etc/php/7.2/cli/conf.d/20-mysql_xdevapi.ini // Let's see which MySQL extensions are enabled now $ php -m |grep mysql mysql_xdevapi mysqli mysqlnd pdo_mysql
Information for installing this PECL extension may be found in the manual chapter titled Installation of PECL extensions. Additional information such as new releases, downloads, source files, maintainer information, and a CHANGELOG, can be located here: » https://pecl.php.net/package/mysql_xdevapi.
Runtime Configuration
The behaviour of these functions is affected by settings in php.ini.
| Name | Default | Changeable | Changelog |
|---|---|---|---|
| xmysqlnd.collect_memory_statistics | 0 | PHP_INI_SYSTEM | |
| xmysqlnd.collect_statistics | 1 | PHP_INI_ALL | |
| xmysqlnd.debug | PHP_INI_SYSTEM | ||
| xmysqlnd.mempool_default_size | 16000 | PHP_INI_ALL | |
| xmysqlnd.net_read_timeout | 31536000 | PHP_INI_SYSTEM | |
| xmysqlnd.trace_alloc | PHP_INI_SYSTEM |
Here's a short explanation of the configuration directives.
Building / Compiling From Source
Considerations for compiling this extension from source.
-
The extension name is 'mysql_xdevapi', so use
--enable-mysql-xdevapi. -
Boost: required, optionally use the --with-boost=DIR configure option or set the MYSQL_XDEVAPI_BOOST_ROOT environment variable. Only the boost header files are required; not the binaries.
-
Google Protocol Buffers (protobuf): required, optionally use the --with-protobuf=DIR configure option or set the MYSQL_XDEVAPI_PROTOBUF_ROOT environment variable.
Optionally use
make protobufsto generate protobuf files (*.pb.cc/.h), andmake clean-protobufsto delete generate protobuf files.Windows specific protobuf note: depending on your environment, the static library with a multi-threaded DLL runtime may be needed. To prepare, use the following options: -Dprotobuf_MSVC_STATIC_RUNTIME=OFF -Dprotobuf_BUILD_SHARED_LIBS=OFF
-
Google Protocol Buffers / protocol compiler (protoc): required, ensure that proper 'protoc' is available in the PATH while building. It is especially important as Windows PHP SDK batch scripts may overwrite the environment.
-
Bison: required, and available from the PATH.
Windows specific bison note: we strongly recommended that bison delivered with the chosen PHP SDKis used else an error similar to "zend_globals_macros.h(39): error C2375: 'zendparse': redefinition; different linkage Zend/zend_language_parser.h(214): note: see declaration of 'zendparse'" may be the result. Also, Windows PHP SDK batch scripts may overwrite the environment.
-
Windows Specific Notes: To prepare the environment, see the official Windows build documentation for » the current SDK.
We recommend using the backslash '\\' instead of a slash '/' for all paths.
Predefined Constants
The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
-
MYSQLX_CLIENT_SSL(integer) -
MYSQLX_TYPE_DECIMAL(integer) -
MYSQLX_TYPE_TINY(integer) -
MYSQLX_TYPE_SHORT(integer) -
MYSQLX_TYPE_SMALLINT(integer) -
MYSQLX_TYPE_MEDIUMINT(integer) -
MYSQLX_TYPE_INT(integer) -
MYSQLX_TYPE_BIGINT(integer) -
MYSQLX_TYPE_LONG(integer) -
MYSQLX_TYPE_FLOAT(integer) -
MYSQLX_TYPE_DOUBLE(integer) -
MYSQLX_TYPE_NULL(integer) -
MYSQLX_TYPE_TIMESTAMP(integer) -
MYSQLX_TYPE_LONGLONG(integer) -
MYSQLX_TYPE_INT24(integer) -
MYSQLX_TYPE_DATE(integer) -
MYSQLX_TYPE_TIME(integer) -
MYSQLX_TYPE_DATETIME(integer) -
MYSQLX_TYPE_YEAR(integer) -
MYSQLX_TYPE_NEWDATE(integer) -
MYSQLX_TYPE_ENUM(integer) -
MYSQLX_TYPE_SET(integer) -
MYSQLX_TYPE_TINY_BLOB(integer) -
MYSQLX_TYPE_MEDIUM_BLOB(integer) -
MYSQLX_TYPE_LONG_BLOB(integer) -
MYSQLX_TYPE_BLOB(integer) -
MYSQLX_TYPE_VAR_STRING(integer) -
MYSQLX_TYPE_STRING(integer) -
MYSQLX_TYPE_CHAR(integer) -
MYSQLX_TYPE_BYTES(integer) -
MYSQLX_TYPE_INTERVAL(integer) -
MYSQLX_TYPE_GEOMETRY(integer) -
MYSQLX_TYPE_JSON(integer) -
MYSQLX_TYPE_NEWDECIMAL(integer) -
MYSQLX_TYPE_BIT(integer) -
MYSQLX_LOCK_DEFAULT(integer) -
MYSQLX_LOCK_NOWAIT(integer) -
MYSQLX_LOCK_SKIP_LOCKED(integer)
Examples
The central entry point to the X DevAPI is the mysql_xdevapi\getSession() function, which receives a URI to a MySQL 8.0 Server and returns a mysql_xdevap\Session object.
Example #1 Connecting to a MySQL Server
<?php
try {
$session = mysql_xdevapi\getSession("mysqlx://user:password@host");
} catch(Exception $e) {
die("Connection could not be established: " . $e->getMessage());
}
// ... use $session
?>
The session provides full access to the API. For a new MySQL Server installation, the first step is to create a database schema with a collection to store data:
Example #2 Creating a Schema and Collection on the MySQL Server
<?php
$schema = $session->createSchema("test");
$collection = $schema->createCollection("example");
?>
When storing data, typically json_encode() is used to encode the data into JSON, which can then be stored inside a collection.
The following example stores data into the collection we created earlier, and then retrieve parts of it again.
Example #3 Storing and Retrieving Data
<?php
$marco = [
"name" => "Marco",
"age" => 19,
"job" => "Programmer"
];
$mike = [
"name" => "Mike",
"age" => 39,
"job" => "Manager"
];
$schema = $session->getSchema("test");
$collection = $schema->getCollection("example");
$collection->add($marco, $mike)->execute();
var_dump($collection->find("name = 'Mike'")->execute()->fetchOne());
?>
The above example will output something similar to:
array(4) {
["_id"]=>
string(28) "00005ad66aaf0000000000000003"
["age"]=>
int(39)
["job"]=>
string(7) "Manager"
["name"]=>
string(4) "Mike"
}
The example demonstrates that the MySQL Server adds an extra field named
_id, which serves as primary key to the document.
The example also demonstrates that retrieved data is sorted alphabetically. That specific order comes from the efficient binary storage inside the MySQL server, but it should not be relied upon. Refer to the MySQL JSON datatype documentation for details.
Optionally use PHP's iterators fetch multiple documents:
Example #4 Fetching and Iterating Multiple Documents
<?php
$result = $collection->find()->execute();
foreach ($result as $doc) {
echo "${doc["name"]} is a ${doc["job"]}.\n";
}
?>
The above example will output something similar to:
Marco is a Programmer. Mike is a Manager.
Mysql_xdevapi Functions
expression
(No version information available, might only be in Git)
expression — Bind prepared statement variables as parameters
Description
$expression
) : object
This function is currently not documented; only its argument list is available.
Parameters
-
expression -
Return Values
Examples
Example #1 mysql_xdevapi\Expression() example
<?php
$expression = mysql_xdevapi\Expression("[age,job]");
$res = $coll->find("age > 30")->fields($expression)->limit(3)->execute();
$data = $res->fetchAll();
print_r($data);
?>
The above example will output something similar to:
<?php
getSession
(No version information available, might only be in Git)
getSession — Connect to a MySQL server
Description
Connects to the MySQL server.
Parameters
-
uri -
The URI to the MySQL server, such as
mysqlx://user:password@host.URI format:
scheme://[user[:[password]]@]target[:port][?attribute1=value1&attribute2=value2...-
scheme: required, the connection protocolIn mysql_xdevapi it is always 'mysqlx' (for X Protocol)
-
user: optional, the MySQL user account for authentication -
password: optional, the MySQL user's password for authentication -
target: required, the server instance the connection refers to:* TCP connection (host name, IPv4 address, or IPv6 address)
* Unix socket path (local file path)
* Windows named-pipe (local file path)
-
port: optional, network port of MySQL server.by default port for X Protocol is 33060
-
?attribute=value: this element is optional and specifies a data dictionary that contains different options, including:-
The
auth(authentication mechanism) attribute as it relates to encrypted connections. For additional information, see » Command Options for Encrypted Connections. The following 'auth' values are supported:plain,mysql41,external, andsha256_mem. -
The
connect-timeoutattribute affects the connection and not subsequent operations. It is set per connection whether on a single or multiple hosts.Pass in a positive integer to define the connection timeout in seconds, or pass in 0 (zero) to disable the timeout (infinite). Not defining connect-timeout uses the default value of 10.
Related, the MYSQLX_CONNECTION_TIMEOUT (timeout in seconds) and MYSQLX_TEST_CONNECTION_TIMEOUT (used while running tests) environment variables can be set and used instead of connect-timeout in the URI. The connect-timeout URI option has precedence over these environment variables.
-
The optional
compressionattribute accepts these values:preferred(client negotiates with server to find a supported algorithm; connection is uncompressed if a mutually supported algorithm is not found),required(like "preferred", but connection is terminated if a mutually supported algorithm is not found), ordisabled(connection is uncompressed). Defaults topreferred.This option was added in version 8.0.20.
-
The optional
compression-algorithmsattribute defines the desired compression algorithms (and their preferred usage order):zstd_stream(alias: zstd),lz4_message(alias: lz4), ordeflate_stream(aliases: deflate or zlib). By default, the order used (depending on system availability) is lz4_message, zstd_stream, then deflate_stream. For example, passing in compression-algorithms=[lz4,zstd_stream] uses lz4 if it's available, otherwise zstd_stream is used. If both are unavailable then behavior depends on the compression value e.g., if compression=required then it'll fail with an error.This option was added in version 8.0.22.
-
Example #1 URI examples
mysqlx://foobar
mysqlx://root@localhost?socket=%2Ftmp%2Fmysqld.sock%2F
mysqlx://foo:bar@localhost:33060
mysqlx://foo:bar@localhost:33160?ssl-mode=disabled
mysqlx://foo:bar@localhost:33260?ssl-mode=required
mysqlx://foo:bar@localhost:33360?ssl-mode=required&auth=mysql41
mysqlx://foo:bar@(/path/to/socket)
mysqlx://foo:bar@(/path/to/socket)?auth=sha256_mem
mysqlx://foo:bar@[localhost:33060, 127.0.0.1:33061]
mysqlx://foobar?ssl-ca=(/path/to/ca.pem)&ssl-crl=(/path/to/crl.pem)
mysqlx://foo:bar@[localhost:33060, 127.0.0.1:33061]?ssl-mode=disabled
mysqlx://foo:bar@localhost:33160/?connect-timeout=0
mysqlx://foo:bar@localhost:33160/?connect-timeout=10&compression=required
mysqlx://foo:bar@localhost:33160/?connect-timeout=10&compression=required&compression-algorithms=[lz4,zstd_stream]For related information, see MySQL Shell's » Connecting using a URI String.
-
Return Values
A Session object.
Errors/Exceptions
A connection failure throws an Exception.
Examples
Example #2 mysql_xdevapi\getSession() example
<?php
try {
$session = mysql_xdevapi\getSession("mysqlx://user:password@host");
} catch(Exception $e) {
die("Connection could not be established: " . $e->getMessage());
}
$schemas = $session->getSchemas();
print_r($schemas);
$mysql_version = $session->getServerVersion();
print_r($mysql_version);
var_dump($collection->find("name = 'Alfred'")->execute()->fetchOne());
?>
The above example will output something similar to:
Array
(
[0] => mysql_xdevapi\Schema Object
(
[name] => helloworld
)
[1] => mysql_xdevapi\Schema Object
(
[name] => information_schema
)
[2] => mysql_xdevapi\Schema Object
(
[name] => mysql
)
[3] => mysql_xdevapi\Schema Object
(
[name] => performance_schema
)
[4] => mysql_xdevapi\Schema Object
(
[name] => sys
)
)
80012
array(4) {
["_id"]=>
string(28) "00005ad66abf0001000400000003"
["age"]=>
int(42)
["job"]=>
string(7) "Butler"
["name"]=>
string(4) "Alfred"
}
Table of Contents
- expression — Bind prepared statement variables as parameters
- getSession — Connect to a MySQL server
BaseResult interface
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
BaseResult::getWarnings
(No version information available, might only be in Git)
BaseResult::getWarnings — Fetch warnings from last operation
Description
Fetches warnings generated by MySQL server's last operation.
Parameters
This function has no parameters.
Return Values
An array of Warning objects from the last operation. Each object defines an error 'message', error 'level', and error 'code'. An empty array is returned if no errors are present.
Examples
Example #1 mysql_xdevapi\RowResult::getWarnings() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("CREATE DATABASE foo")->execute();
$session->sql("CREATE TABLE foo.test_table(x int)")->execute();
$schema = $session->getSchema("foo");
$table = $schema->getTable("test_table");
$table->insert(['x'])->values([1])->values([2])->execute();
$res = $table->select(['x/0 as bad_x'])->execute();
$warnings = $res->getWarnings();
print_r($warnings);
?>
The above example will output something similar to:
Array
(
[0] => mysql_xdevapi\Warning Object
(
[message] => Division by 0
[level] => 2
[code] => 1365
)
[1] => mysql_xdevapi\Warning Object
(
[message] => Division by 0
[level] => 2
[code] => 1365
)
)
BaseResult::getWarningsCount
(No version information available, might only be in Git)
BaseResult::getWarningsCount — Fetch warning count from last operation
Description
Returns the number of warnings raised by the last operation. Specifically, these warnings are raised by the MySQL server.
Parameters
This function has no parameters.
Return Values
The number of warnings from the last operation.
Examples
Example #1 mysql_xdevapi\RowResult::getWarningsCount() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS foo")->execute();
$session->sql("CREATE DATABASE foo")->execute();
$session->sql("CREATE TABLE foo.test_table(x int)")->execute();
$schema = $session->getSchema("foo");
$table = $schema->getTable("test_table");
$table->insert(['x'])->values([1])->values([2])->execute();
$res = $table->select(['x/0 as bad_x'])->execute();
echo $res->getWarningsCount();
?>
The above example will output something similar to:
2
Table of Contents
- BaseResult::getWarnings — Fetch warnings from last operation
- BaseResult::getWarningsCount — Fetch warning count from last operation
Client class
(No version information available, might only be in Git)
Introduction
Provides access to the connection pool.
Class synopsis
mysql_xdevapi\Client::close
(No version information available, might only be in Git)
mysql_xdevapi\Client::close — Close client
Description
Close all client connections with the server.
Parameters
This function has no parameters.
Return Values
TRUE if connections are closed.
Client::__construct
(No version information available, might only be in Git)
Client::__construct — Client constructor
Description
Construct a client object.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\Client::__construct() example
<?php
$pooling_options = '{
"enabled": true,
"maxSize": 10,
"maxIdleTime": 3600,
"queueTimeOut": 1000
}';
$client = mysql_xdevapi\getClient($connection_uri, $pooling_options);
$session = $client->getSession();
Client::getClient
(No version information available, might only be in Git)
Client::getClient — Get client session
Description
Get session associated with the client.
Parameters
This function has no parameters.
Return Values
A Session object.
Table of Contents
- mysql_xdevapi\Client::close — Close client
- Client::__construct — Client constructor
- Client::getClient — Get client session
Collection class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
$index_name
, string $index_desc_json
) : void$index_name
) : bool$id
) : DocumentProperties
- name
Collection::add
(No version information available, might only be in Git)
Collection::add — Add collection document
Description
Triggers the insertion of the given document(s) into the collection, and multiple variants of this method are supported. Options include:
-
Add a single document as a JSON string.
-
Add a single document as an array as:
[ 'field' => 'value', 'field2' => 'value2' ... ] -
A mix of both, and multiple documents can be added in the same operation.
Parameters
-
document -
One or multiple documents, and this can be either JSON or an array of fields with their associated values. This cannot be an empty array.
The MySQL server automatically generates unique
_idvalues for each document (recommended), although this can be manually added as well. This value must be unique as otherwise the add operation will fail.
Return Values
A CollectionAdd object. Use execute() to return a Result that can be used to query the number of affected items, the number warnings generated by the operation, or to fetch a list of generated IDs for the inserted documents.
Examples
Example #1 mysql_xdevapi\Collection::add() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$collection = $schema->getCollection("people");
// Add two documents
$collection->add('{"name": "Fred", "age": 21, "job": "Construction"}')->execute();
$collection->add('{"name": "Wilma", "age": 23, "job": "Teacher"}')->execute();
// Add two documents using a single JSON object
$result = $collection->add(
'{"name": "Bernie",
"jobs": [{"title":"Cat Herder","Salary":42000}, {"title":"Father","Salary":0}],
"hobbies": ["Sports","Making cupcakes"]}',
'{"name": "Jane",
"jobs": [{"title":"Scientist","Salary":18000}, {"title":"Mother","Salary":0}],
"hobbies": ["Walking","Making pies"]}')->execute();
// Fetch a list of generated ID's from the last add()
$ids = $result->getGeneratedIds();
print_r($ids);
?>
The above example will output something similar to:
Array
(
[0] => 00005b6b53610000000000000056
[1] => 00005b6b53610000000000000057
)
Notes
Note:
A unique _id is generated by MySQL Server 8.0 or higher, as demonstrated in the example. The _id field must be manually defined if using MySQL Server 5.7.
Collection::addOrReplaceOne
(No version information available, might only be in Git)
Collection::addOrReplaceOne — Add or replace collection document
Description
$id
, string $doc
) : mysql_xdevapi\ResultAdd a new document, or replace a document if it already exists.
Here are several scenarios for this method:
-
If neither the id or any unique key values conflict with any document in the collection, then the document is added.
-
If the id does not match any document but one or more unique key values conflict with a document in the collection, then an error is raised.
-
If id matches an existing document and no unique keys are defined for the collection, then the document is replaced.
-
If id matches an existing document, and either all unique keys in the replacement document match that same document or they don't conflict with any other documents in the collection, then the document is replaced.
-
If id matches an existing document and one or more unique keys match a different document from the collection, then an error is raised.
Parameters
-
id -
This is the filter id. If this id or any other field that has a unique index already exists in the collection, then it will update the matching document instead.
By default, this id is automatically generated by MySQL Server when the record was added, and is referenced as a field named '_id'.
-
doc -
This is the document to add or replace, which is a JSON string.
Return Values
A Result object.
Examples
Example #1 mysql_xdevapi\Collection::addOrReplaceOne() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$collection = $schema->getCollection("people");
// Using add()
$result = $collection->add('{"name": "Wilma", "age": 23, "job": "Teacher"}')->execute();
// Using addOrReplaceOne()
// Note: we're passing in a known _id value here
$result = $collection->addOrReplaceOne('00005b6b53610000000000000056', '{"name": "Fred", "age": 21, "job": "Construction"}');
?>
Collection::__construct
(No version information available, might only be in Git)
Collection::__construct — Collection constructor
Description
Construct a Collection object.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\Collection::getOne() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$result = $collection->add('{"name": "Alfred", "age": 42, "job": "Butler"}')->execute();
// A unique _id is (by default, and recommended) generated by MySQL Server
// This retrieves the generated _id's; only one in this example, so $ids[0]
$ids = $result->getGeneratedIds();
$alfreds_id = $ids[0];
// ...
print_r($alfreds_id);
print_r($collection->getOne($alfreds_id));
?>
The above example will output something similar to:
00005b6b536100000000000000b1
Array
(
[_id] => 00005b6b536100000000000000b1
[age] => 42
[job] => Butler
[name] => Alfred
)
Collection::count
(No version information available, might only be in Git)
Collection::count — Get document count
Description
This functionality is similar to a SELECT COUNT(*) SQL
operation against the MySQL server for the current schema and collection.
In other words, it counts the number of documents in the collection.
Parameters
This function has no parameters.
Return Values
The number of documents in the collection.
Examples
Example #1 mysql_xdevapi\Collection::count() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$collection = $schema->getCollection("people");
$result = $collection
->add(
'{"name": "Bernie",
"jobs": [
{"title":"Cat Herder","Salary":42000},
{"title":"Father","Salary":0}
],
"hobbies": ["Sports","Making cupcakes"]}',
'{"name": "Jane",
"jobs": [
{"title":"Scientist","Salary":18000},
{"title":"Mother","Salary":0}
],
"hobbies": ["Walking","Making pies"]}')
->execute();
var_dump($collection->count());
?>
The above example will output:
int(2)
Collection::createIndex
(No version information available, might only be in Git)
Collection::createIndex — Create collection index
Description
$index_name
, string $index_desc_json
) : voidCreates an index on the collection.
An exception is thrown if an index with the same name already exists, or if index definition is not correctly formed.
Parameters
-
index_name -
The name of the index that to create. This name must be a valid index name as accepted by the
CREATE INDEXSQL query. -
index_desc_json -
Definition of the index to create. It contains an array of IndexField objects, and each object describes a single document member to include in the index, and an optional string for the type of index that might be INDEX (default) or SPATIAL.
A single IndexField description consists of the following fields:
-
field: string, the full document path to the document member or field to be indexed. -
type: string, one of the supported SQL column types to map the field into. For numeric types, the optional UNSIGNED keyword may follow. For the TEXT type, the length to consider for indexing may be added. -
required: bool, (optional) true if the field is required to exist in the document. Defaults toFALSE, except forGEOJSONwhere it defaults toTRUE. -
options: integer, (optional) special option flags for use when decodingGEOJSONdata. -
srid: integer, (optional) srid value for use when decodingGEOJSONdata.
It is an error to include other fields not described above in IndexDefinition or IndexField documents.
-
Return Values
Examples
Example #1 mysql_xdevapi\Collection::createIndex() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
// Creating a text index
$collection->createIndex(
'myindex1',
'{"fields": [{
"field": "$.name",
"type": "TEXT(25)",
"required": true}],
"unique": false}'
);
// A spatial index
$collection->createIndex(
'myindex2',
'{"fields": [{
"field": "$.home",
"type": "GEOJSON",
"required": true}],
"type": "SPATIAL"}'
);
// Index with multiple fields
$collection->createIndex(
'myindex3',
'{"fields": [
{
"field": "$.name",
"type": "TEXT(20)",
"required": true
},
{
"field": "$.age",
"type": "INTEGER"
},
{
"field": "$.job",
"type": "TEXT(30)",
"required": false
}
],
"unique": true
}'
);
Collection::dropIndex
(No version information available, might only be in Git)
Collection::dropIndex — Drop collection index
Description
$index_name
) : boolDrop a collection index.
This operation does not yield an error if the index does not exist, but
FALSE is returned in that case.
Parameters
-
index_name -
Name of collection index to drop.
Return Values
TRUE if the DROP INDEX operation succeeded, otherwise FALSE.
Examples
Example #1 mysql_xdevapi\Collection::dropIndex() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
// ...
$collection = $schema->getCollection("people");
$collection->createIndex(
'myindex',
'{"fields": [{"field": "$.name", "type": "TEXT(25)", "required": true}], "unique": false}'
);
// ...
if ($collection->dropIndex('myindex')) {
echo 'An index named 'myindex' was found, and dropped.';
}
?>
The above example will output:
An index named 'myindex' was found, and dropped.
Collection::existsInDatabase
(No version information available, might only be in Git)
Collection::existsInDatabase — Check if collection exists in database
Description
Checks if the Collection object refers to a collection in the database (schema).
Parameters
This function has no parameters.
Return Values
Returns TRUE if collection exists in the database, else FALSE if it does not.
Examples
Example #1 mysql_xdevapi\Collection::existsInDatabase() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
// ...
$collection = $schema->getCollection("people");
// ...
if (!$collection->existsInDatabase()) {
echo "The collection no longer exists in the database named addressbook. What happened?";
}
?>
Collection::find
(No version information available, might only be in Git)
Collection::find — Search for document
Description
$search_condition
] ) : mysql_xdevapi\CollectionFindSearch a database collection for a document or set of documents. The found documents are returned as a CollectionFind object is to further modify or fetch results from.
Parameters
-
search_condition -
Although optional, normally a condition is defined to limit the results to a subset of documents.
Multiple elements might build the condition and the syntax supports parameter binding. The expression used as search condition must be a valid SQL expression. If no search condition is provided (field empty) then find('true') is assumed.
Return Values
A CollectionFind object to verify the operation, or fetch the found documents.
Examples
Example #1 mysql_xdevapi\Collection::find() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$collection->add('{"name": "Alfred", "age": 18, "job": "Butler"}')->execute();
$collection->add('{"name": "Bob", "age": 19, "job": "Swimmer"}')->execute();
$collection->add('{"name": "Fred", "age": 20, "job": "Construction"}')->execute();
$collection->add('{"name": "Wilma", "age": 21, "job": "Teacher"}')->execute();
$collection->add('{"name": "Suki", "age": 22, "job": "Teacher"}')->execute();
$find = $collection->find('job LIKE :job AND age > :age');
$result = $find
->bind(['job' => 'Teacher', 'age' => 20])
->sort('age DESC')
->limit(2)
->execute();
print_r($result->fetchAll());
?>
The above example will output:
Array
(
[0] => Array
(
[_id] => 00005b6b536100000000000000a8
[age] => 22
[job] => Teacher
[name] => Suki
)
[1] => Array
(
[_id] => 00005b6b536100000000000000a7
[age] => 21
[job] => Teacher
[name] => Wilma
)
)
Collection::getName
(No version information available, might only be in Git)
Collection::getName — Get collection name
Description
Retrieve the collection's name.
Parameters
This function has no parameters.
Return Values
The collection name, as a string.
Examples
Example #1 mysql_xdevapi\Collection::getName() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
// ...
var_dump($collection->getName());
?>
The above example will output something similar to:
string(6) "people"
Collection::getOne
(No version information available, might only be in Git)
Collection::getOne — Get one document
Description
$id
) : DocumentFetches one document from the collection.
This is a shortcut for:
Collection.find("_id = :id").bind("id", id).execute().fetchOne();
Parameters
-
id -
The document _id in the collection.
Return Values
The collection object, or NULL if the _id does not match a document.
Examples
Example #1 mysql_xdevapi\Collection::getOne() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$result = $collection->add('{"name": "Alfred", "age": 42, "job": "Butler"}')->execute();
// A unique _id is (by default, and recommended) generated by MySQL Server
// This retrieves the generated _id's; only one in this example, so $ids[0]
$ids = $result->getGeneratedIds();
$alfreds_id = $ids[0];
// ...
print_r($alfreds_id);
print_r($collection->getOne($alfreds_id));
?>
The above example will output something similar to:
00005b6b536100000000000000b1
Array
(
[_id] => 00005b6b536100000000000000b1
[age] => 42
[job] => Butler
[name] => Alfred
)
Collection::getSchema
(No version information available, might only be in Git)
Collection::getSchema — Get schema object
Description
Retrieve the schema object that contains the collection.
Parameters
This function has no parameters.
Return Values
The schema object on success, or NULL if the object cannot be retrieved
for the given collection.
Examples
Example #1 mysql_xdevapi\Collection::getSchema() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
var_dump($collection->getSchema());
?>
The above example will output something similar to:
object(mysql_xdevapi\Schema)#9 (1) {
["name"]=>
string(11) "addressbook"
}
Collection::getSession
(No version information available, might only be in Git)
Collection::getSession — Get session object
Description
Get a new Session object from the Collection object.
Parameters
This function has no parameters.
Return Values
A Session object.
Examples
Example #1 mysql_xdevapi\Collection::getSession() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
// ...
$newsession = $collection->getSession();
var_dump($session);
var_dump($newsession);
?>
The above example will output something similar to:
object(mysql_xdevapi\Session)#1 (0) {
}
object(mysql_xdevapi\Session)#4 (0) {
}
Collection::modify
(No version information available, might only be in Git)
Collection::modify — Modify collection documents
Description
$search_condition
) : mysql_xdevapi\CollectionModifyModify collections that meet specific search conditions. Multiple operations are allowed, and parameter binding is supported.
Parameters
-
search_condition -
Must be a valid SQL expression used to match the documents to modify. This expression might be as simple as
TRUE, which matches all documents, or it might use functions and operators such as'CAST(_id AS SIGNED) >= 10','age MOD 2 = 0 OR age MOD 3 = 0', or'_id IN ["2","5","7","10"]'.
Return Values
If the operation is not executed, then the function will return a Modify object that can be used to add additional modify operations.
If the modify operation is executed, then the returned object will contain the result of the operation.
Examples
Example #1 mysql_xdevapi\Collection::modify() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$collection->add('{"name": "Alfred", "age": 18, "job": "Butler"}')->execute();
$collection->add('{"name": "Bob", "age": 19, "job": "Painter"}')->execute();
// Add two new jobs for all Painters: Artist and Crafter
$collection
->modify("job in ('Butler', 'Painter')")
->arrayAppend('job', 'Artist')
->arrayAppend('job', 'Crafter')
->execute();
// Remove the 'beer' field from all documents with the age 21
$collection
->modify('age < 21')
->unset(['beer'])
->execute();
?>
Collection::remove
(No version information available, might only be in Git)
Collection::remove — Remove collection documents
Description
$search_condition
) : mysql_xdevapi\CollectionRemoveRemove collections that meet specific search conditions. Multiple operations are allowed, and parameter binding is supported.
Parameters
-
search_condition -
Must be a valid SQL expression used to match the documents to modify. This expression might be as simple as
TRUE, which matches all documents, or it might use functions and operators such as'CAST(_id AS SIGNED) >= 10','age MOD 2 = 0 OR age MOD 3 = 0', or'_id IN ["2","5","7","10"]'.
Return Values
If the operation is not executed, then the function will return a Remove object that can be used to add additional remove operations.
If the remove operation is executed, then the returned object will contain the result of the operation.
Examples
Example #1 mysql_xdevapi\Collection::remove() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$collection->add('{"name": "Alfred", "age": 18, "job": "Butler"}')->execute();
$collection->add('{"name": "Bob", "age": 19, "job": "Painter"}')->execute();
// Remove all painters
$collection
->remove("job in ('Painter')")
->execute();
// Remove the oldest butler
$collection
->remove("job in ('Butler')")
->sort('age desc')
->limit(1)
->execute();
// Remove record with lowest age
$collection
->remove('true')
->sort('age desc')
->limit(1)
->execute();
?>
Collection::removeOne
(No version information available, might only be in Git)
Collection::removeOne — Remove one collection document
Description
Remove one document from the collection with the correspending ID.
This is a shortcut for Collection.remove("_id = :id").bind("id", id).execute().
Parameters
-
id -
The ID of the collection document to remove. Typically this is the _id that was generated by MySQL Server when the record was added.
Return Values
A Result object that can be used to query the number of affected items or the number warnings generated by the operation.
Examples
Example #1 mysql_xdevapi\Collection::removeOne() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$result = $collection->add('{"name": "Alfred", "age": 18, "job": "Butler"}')->execute();
// Normally the _id is known by other means,
// but for this example let's fetch the generated id and use it
$ids = $result->getGeneratedIds();
$alfred_id = $ids[0];
$result = $collection->removeOne($alfred_id);
if(!$result->getAffectedItemsCount()) {
echo "Alfred with id $alfred_id was not removed.";
} else {
echo "Goodbye, Alfred, you can take _id $alfred_id with you.";
}
?>
The above example will output something similar to:
Goodbye, Alfred, you can take _id 00005b6b536100000000000000cb with you.
Collection::replaceOne
(No version information available, might only be in Git)
Collection::replaceOne — Replace one collection document
Description
Updates (or replaces) the document identified by ID, if it exists.
Parameters
-
id -
ID of the document to replace or update. Typically this is the _id that was generated by MySQL Server when the record was added.
-
doc -
Collection document to update or replace the document matching the id parameter.
This document can be either a document object or a valid JSON string describing the new document.
Return Values
A Result object that can be used to query the number of affected items and the number warnings generated by the operation.
Examples
Example #1 mysql_xdevapi\Collection::replaceOne() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$result = $collection->add('{"name": "Alfred", "age": 18, "job": "Butler"}')->execute();
// Normally the _id is known by other means,
// but for this example let's fetch the generated id and use it
$ids = $result->getGeneratedIds();
$alfred_id = $ids[0];
// ...
$alfred = $collection->getOne($alfred_id);
$alfred['age'] = 81;
$alfred['job'] = 'Guru';
$collection->replaceOne($alfred_id, $alfred);
?>
Table of Contents
- Collection::add — Add collection document
- Collection::addOrReplaceOne — Add or replace collection document
- Collection::__construct — Collection constructor
- Collection::count — Get document count
- Collection::createIndex — Create collection index
- Collection::dropIndex — Drop collection index
- Collection::existsInDatabase — Check if collection exists in database
- Collection::find — Search for document
- Collection::getName — Get collection name
- Collection::getOne — Get one document
- Collection::getSchema — Get schema object
- Collection::getSession — Get session object
- Collection::modify — Modify collection documents
- Collection::remove — Remove collection documents
- Collection::removeOne — Remove one collection document
- Collection::replaceOne — Replace one collection document
CollectionAdd class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
CollectionAdd::__construct
(No version information available, might only be in Git)
CollectionAdd::__construct — CollectionAdd constructor
Description
Use to add a document to a collection; called from a Collection object.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\CollectionAdd::__construct() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$collection = $schema->getCollection("people");
// Add two documents
$collection
->add('{"name": "Fred", "age": 21, "job": "Construction"}')
->execute();
$collection
->add('{"name": "Wilma", "age": 23, "job": "Teacher"}')
->execute();
// Add two documents using a single JSON object
$result = $collection
->add(
'{"name": "Bernie",
"jobs": [{"title":"Cat Herder","Salary":42000}, {"title":"Father","Salary":0}],
"hobbies": ["Sports","Making cupcakes"]}',
'{"name": "Jane",
"jobs": [{"title":"Scientist","Salary":18000}, {"title":"Mother","Salary":0}],
"hobbies": ["Walking","Making pies"]}')
->execute();
// Fetch a list of generated ID's from the last add()
$ids = $result->getGeneratedIds();
print_r($ids);
?>
The above example will output something similar to:
Array
(
[0] => 00005b6b53610000000000000056
[1] => 00005b6b53610000000000000057
)
Notes
Note:
A unique _id is generated by MySQL Server 8.0 or higher, as demonstrated in the example. The _id field must be manually defined if using MySQL Server 5.7.
CollectionAdd::execute
(No version information available, might only be in Git)
CollectionAdd::execute — Execute the statement
Description
The execute method is required to send the CRUD operation request to the MySQL server.
Parameters
This function has no parameters.
Return Values
A Result object that can be used to verify the status of the operation, such as the number of affected rows.
Examples
Example #1 mysql_xdevapi\CollectionAdd::execute() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$collection = $schema->getCollection("people");
// Add two documents
$collection
->add('{"name": "Fred", "age": 21, "job": "Construction"}')
->execute();
$collection
->add('{"name": "Wilma", "age": 23, "job": "Teacher"}')
->execute();
// Add two documents using a single JSON object
$result = $collection
->add(
'{"name": "Bernie",
"jobs": [{"title":"Cat Herder","Salary":42000}, {"title":"Father","Salary":0}],
"hobbies": ["Sports","Making cupcakes"]}',
'{"name": "Jane",
"jobs": [{"title":"Scientist","Salary":18000}, {"title":"Mother","Salary":0}],
"hobbies": ["Walking","Making pies"]}')
->execute();
// Fetch a list of generated ID's from the last add()
$ids = $result->getGeneratedIds();
print_r($ids);
?>
The above example will output something similar to:
Array
(
[0] => 00005b6b53610000000000000056
[1] => 00005b6b53610000000000000057
)
Table of Contents
- CollectionAdd::__construct — CollectionAdd constructor
- CollectionAdd::execute — Execute the statement
CollectionFind class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
CollectionFind::bind
(No version information available, might only be in Git)
CollectionFind::bind — Bind value to query placeholder
Description
$placeholder_values
) : mysql_xdevapi\CollectionFindIt allows the user to bind a parameter to the placeholder in the search condition of the find operation. The placeholder has the form of :NAME where ':' is a common prefix that must always exists before any NAME, NAME is the actual name of the placeholder. The bind function accepts a list of placeholders if multiple entities have to be substituted in the search condition.
Parameters
-
placeholder_values -
Values to substitute in the search condition; multiple values are allowed and are passed as an array where "PLACEHOLDER_NAME => PLACEHOLDER_VALUE".
Return Values
A CollectionFind object, or chain with execute() to return a Result object.
Examples
Example #1 mysql_xdevapi\CollectionFind::bind() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$result = $create
->add('{"name": "Alfred", "age": 18, "job": "Butler"}')
->execute();
// ...
$collection = $schema->getCollection("people");
$result = $collection
->find('job like :job and age > :age')
->bind(['job' => 'Butler', 'age' => 16])
->execute();
var_dump($result->fetchAll());
?>
The above example will output something similar to:
array(1) {
[0]=>
array(4) {
["_id"]=>
string(28) "00005b6b536100000000000000cf"
["age"]=>
int(18)
["job"]=>
string(6) "Butler"
["name"]=>
string(6) "Alfred"
}
}
CollectionFind::__construct
(No version information available, might only be in Git)
CollectionFind::__construct — CollectionFind constructor
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Examples
Example #1 CollectionFind example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$result = $create
->add('{"name": "Alfred", "age": 18, "job": "Butler"}')
->execute();
// ...
$collection = $schema->getCollection("people");
$result = $collection
->find('job like :job and age > :age')
->bind(['job' => 'Butler', 'age' => 16])
->execute();
var_dump($result->fetchAll());
?>
The above example will output something similar to:
array(1) {
[0]=>
array(4) {
["_id"]=>
string(28) "00005b6b536100000000000000cf"
["age"]=>
int(18)
["job"]=>
string(6) "Butler"
["name"]=>
string(6) "Alfred"
}
}
CollectionFind::execute
(No version information available, might only be in Git)
CollectionFind::execute — Execute the statement
Description
Execute the find operation; this functionality allows for method chaining.
Parameters
This function has no parameters.
Return Values
A DocResult object that to either fetch results from, or to query the status of the operation.
Examples
Example #1 CollectionFind example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$create
->add('{"name": "Alfred", "age": 18, "job": "Butler"}')
->execute();
// ...
$collection = $schema->getCollection("people");
$result = $collection
->find('job like :job and age > :age')
->bind(['job' => 'Butler', 'age' => 16])
->execute();
var_dump($result->fetchAll());
?>
The above example will output something similar to:
array(1) {
[0]=>
array(4) {
["_id"]=>
string(28) "00005b6b536100000000000000cf"
["age"]=>
int(18)
["job"]=>
string(6) "Butler"
["name"]=>
string(6) "Alfred"
}
}
CollectionFind::fields
(No version information available, might only be in Git)
CollectionFind::fields — Set document field filter
Description
Defined the columns for the query to return. If not defined then all columns are used.
Parameters
-
projection -
Can either be a single string or an array of string, those strings are identifying the columns that have to be returned for each document that match the search condition.
Return Values
A CollectionFind object that can be used for further processing.
Examples
Example #1 mysql_xdevapi\CollectionFind::fields() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$create
->add('{"name": "Alfred", "age": 18, "job": "Butler"}')
->execute();
// ...
$collection = $schema->getCollection("people");
$result = $collection
->find('job like :job and age > :age')
->bind(['job' => 'Butler', 'age' => 16])
->fields('name')
->execute();
var_dump($result->fetchAll());
?>
The above example will output something similar to:
array(1) {
[0]=>
array(1) {
["name"]=>
string(6) "Alfred"
}
}
CollectionFind::groupBy
(No version information available, might only be in Git)
CollectionFind::groupBy — Set grouping criteria
Description
This function can be used to group the result-set by one more columns, frequently this is used with aggregate functions like COUNT,MAX,MIN,SUM etc.
Parameters
-
sort_expr -
The columns or columns that have to be used for the group operation, this can either be a single string or an array of string arguments, one for each column.
Return Values
A CollectionFind that can be used for further processing
Examples
Example #1 mysql_xdevapi\CollectionFind::groupBy() example
<?php
//Assuming $coll is a valid Collection object
//Extract all the documents from the Collection and group the results by the 'name' field
$res = $coll->find()->groupBy('name')->execute();
?>
CollectionFind::having
(No version information available, might only be in Git)
CollectionFind::having — Set condition for aggregate functions
Description
This function can be used after the 'field' operation in order to make a selection on the documents to extract.
Parameters
-
sort_expr -
This must be a valid SQL expression, the use of aggreate functions is allowed
Return Values
CollectionFind object that can be used for further processing
Examples
Example #1 mysql_xdevapi\CollectionFind::having() example
<?php
//Assuming $coll is a valid Collection object
//Find all the documents for which the 'age' is greather than 40,
//Only the columns 'name' and 'age' are returned in the Result object
$res = $coll->find()->fields(['name','age'])->having('age > 40')->execute();
?>
CollectionFind::limit
(No version information available, might only be in Git)
CollectionFind::limit — Limit number of returned documents
Description
Set the maximum number of documents to return.
Parameters
-
rows -
Maximum number of documents.
Return Values
A CollectionFind object that can be used for additional processing; chain with the execute() method to return a DocResult object.
Examples
Example #1 mysql_xdevapi\CollectionFind::limit() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$create
->add('{"name": "Alfred", "age": 18, "job": "Butler"}')
->execute();
$create
->add('{"name": "Reginald", "age": 42, "job": "Butler"}')
->execute();
// ...
$collection = $schema->getCollection("people");
$result = $collection
->find('job like :job and age > :age')
->bind(['job' => 'Butler', 'age' => 16])
->sort('age desc')
->limit(1)
->execute();
var_dump($result->fetchAll());
?>
The above example will output something similar to:
array(1) {
[0]=>
array(4) {
["_id"]=>
string(28) "00005b6b536100000000000000f3"
["age"]=>
int(42)
["job"]=>
string(6) "Butler"
["name"]=>
string(8) "Reginald"
}
}
CollectionFind::lockExclusive
(No version information available, might only be in Git)
CollectionFind::lockExclusive — Execute operation with EXCLUSIVE LOCK
Description
$lock_waiting_option
] ) : mysql_xdevapi\CollectionFindLock exclusively the document, other transactions are blocked from updating the document until the document is locked While the document is locked, other transactions are blocked from updating those docs, from doing SELECT ... LOCK IN SHARE MODE, or from reading the data in certain transaction isolation levels. Consistent reads ignore any locks set on the records that exist in the read view.
This feature is directly useful with the modify() command, to avoid concurrency problems. Basically, it serializes access to a row through row locking
Parameters
-
lock_waiting_option -
Optional waiting option. By default it is
MYSQLX_LOCK_DEFAULT. Valid values are these constants:MYSQLX_LOCK_DEFAULTMYSQLX_LOCK_NOWAITMYSQLX_LOCK_SKIP_LOCKED
Return Values
Returns a CollectionFind object that can be used for further processing
Examples
Example #1 mysql_xdevapi\CollectionFind::lockExclusive() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$session->startTransaction();
$result = $collection
->find("age > 50")
->lockExclusive()
->execute();
// ... do an operation on the object
// Complete the transaction and unlock the document
$session->commit();
?>
CollectionFind::offset
(No version information available, might only be in Git)
CollectionFind::offset — Skip given number of elements to be returned
Description
Skip (offset) these number of elements that otherwise would be returned by the find operation. Use with the limit() method.
Defining an offset larger than the result set size results in an empty set.
Parameters
-
position -
Number of elements to skip for the limit() operation.
Return Values
A CollectionFind object that can be used for additional processing.
Examples
Example #1 mysql_xdevapi\CollectionFind::offset() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$create
->add('{"name": "Alfred", "age": 18, "job": "Butler"}')
->execute();
$create
->add('{"name": "Reginald", "age": 42, "job": "Butler"}')
->execute();
// ...
$collection = $schema->getCollection("people");
$result = $collection
->find()
->sort('age asc')
->offset(1)
->limit(1)
->execute();
var_dump($result->fetchAll());
?>
The above example will output something similar to:
array(1) {
[0]=>
array(4) {
["_id"]=>
string(28) "00005b6b536100000000000000f3"
["age"]=>
int(42)
["job"]=>
string(6) "Butler"
["name"]=>
string(8) "Reginald"
}
}
CollectionFind::sort
(No version information available, might only be in Git)
CollectionFind::sort — Set the sorting criteria
Description
Sort the result set by the field selected in the sort_expr argument. The allowed orders are ASC (Ascending) or DESC (Descending). This operation is equivalent to the 'ORDER BY' SQL operation and it follows the same set of rules.
Parameters
-
sort_expr -
One or more sorting expressions can be provided. The evaluation is from left to right, and each expression is separated by a comma.
Return Values
A CollectionFind object that can be used to execute the command, or to add additional operations.
Examples
Example #1 mysql_xdevapi\CollectionFind::sort() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$create
->add('{"name": "Alfred", "age": 18, "job": "Butler"}')
->execute();
$create
->add('{"name": "Reginald", "age": 42, "job": "Butler"}')
->execute();
// ...
$collection = $schema->getCollection("people");
$result = $collection
->find()
->sort('job desc', 'age asc')
->execute();
var_dump($result->fetchAll());
?>
The above example will output something similar to:
array(2) {
[0]=>
array(4) {
["_id"]=>
string(28) "00005b6b53610000000000000106"
["age"]=>
int(18)
["job"]=>
string(6) "Butler"
["name"]=>
string(6) "Alfred"
}
[1]=>
array(4) {
["_id"]=>
string(28) "00005b6b53610000000000000107"
["age"]=>
int(42)
["job"]=>
string(6) "Butler"
["name"]=>
string(8) "Reginald"
}
}
Table of Contents
- CollectionFind::bind — Bind value to query placeholder
- CollectionFind::__construct — CollectionFind constructor
- CollectionFind::execute — Execute the statement
- CollectionFind::fields — Set document field filter
- CollectionFind::groupBy — Set grouping criteria
- CollectionFind::having — Set condition for aggregate functions
- CollectionFind::limit — Limit number of returned documents
- CollectionFind::lockExclusive — Execute operation with EXCLUSIVE LOCK
- CollectionFind::lockShared — Execute operation with SHARED LOCK
- CollectionFind::offset — Skip given number of elements to be returned
- CollectionFind::sort — Set the sorting criteria
CollectionModify class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
$collection_field
, string $expression_or_literal
) : mysql_xdevapi\CollectionModify$collection_field
, string $expression_or_literal
) : mysql_xdevapi\CollectionModify$collection_field
, string $expression_or_literal
) : mysql_xdevapi\CollectionModify$collection_field
, string $expression_or_literal
) : mysql_xdevapi\CollectionModifyCollectionModify::arrayAppend
(No version information available, might only be in Git)
CollectionModify::arrayAppend — Append element to an array field
Description
$collection_field
, string $expression_or_literal
) : mysql_xdevapi\CollectionModifyAdd an element to a document's field, as multiple elements of a field are represented as an array. Unlike arrayInsert(), arrayAppend() always appends the new element at the end of the array, whereas arrayInsert() can define the location.
Parameters
-
collection_field -
The identifier of the field where the new element is inserted.
-
expression_or_literal -
The new element to insert at the end of the document field array.
Return Values
A CollectionModify object that can be used to execute the command, or to add additional operations.
Examples
Example #1 mysql_xdevapi\CollectionModify::arrayAppend() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$result = $collection
->add(
'{"name": "Bernie",
"traits": ["Friend", "Brother", "Human"]}')
->execute();
$collection
->modify("name in ('Bernie', 'Jane')")
->arrayAppend('traits', 'Happy')
->execute();
$result = $collection
->find()
->execute();
print_r($result->fetchAll());
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[_id] => 00005b6b5361000000000000010c
[name] => Bernie
[traits] => Array
(
[0] => Friend
[1] => Brother
[2] => Human
[3] => Happy
)
)
)
CollectionModify::arrayInsert
(No version information available, might only be in Git)
CollectionModify::arrayInsert — Insert element into an array field
Description
$collection_field
, string $expression_or_literal
) : mysql_xdevapi\CollectionModifyAdd an element to a document's field, as multiple elements of a field are represented as an array. Unlike arrayAppend(), arrayInsert() allows you to specify where the new element is inserted by defining which item it is after, whereas arrayAppend() always appends the new element at the end of the array.
Parameters
-
collection_field -
Identify the item in the array that the new element is inserted after. The format of this parameter is
FIELD_NAME[ INDEX ]where FIELD_NAME is the name of the document field to remove the element from, and INDEX is the INDEX of the element within the field.The INDEX field is zero based, so the leftmost item from the array has an index of 0.
-
expression_or_literal -
The new element to insert after FIELD_NAME[ INDEX ]
Return Values
A CollectionModify object that can be used to execute the command, or to add additional operations
Examples
Example #1 mysql_xdevapi\CollectionModify::arrayInsert() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$result = $collection
->add(
'{"name": "Bernie",
"traits": ["Friend", "Brother", "Human"]}')
->execute();
$collection
->modify("name in ('Bernie', 'Jane')")
->arrayInsert('traits[1]', 'Happy')
->execute();
$result = $collection
->find()
->execute();
print_r($result->fetchAll());
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[_id] => 00005b6b5361000000000000010d
[name] => Bernie
[traits] => Array
(
[0] => Friend
[1] => Happy
[2] => Brother
[3] => Human
)
)
)
CollectionModify::bind
(No version information available, might only be in Git)
CollectionModify::bind — Bind value to query placeholder
Description
$placeholder_values
) : mysql_xdevapi\CollectionModifyBind a parameter to the placeholder in the search condition of the modify operation.
The placeholder has the form of :NAME where ':' is a common prefix that must always exists before any NAME where NAME is the name of the placeholder. The bind method accepts a list of placeholders if multiple entities have to be substituted in the search condition of the modify operation.
Parameters
-
placeholder_values -
Placeholder values to substitute in the search condition. Multiple values are allowed and have to be passed as an array of mappings PLACEHOLDER_NAME->PLACEHOLDER_VALUE.
Return Values
A CollectionModify object that can be used to execute the command, or to add additional operations.
Examples
Example #1 mysql_xdevapi\CollectionModify::bind() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$result = $collection
->add(
'{"name": "Bernie",
"traits": ["Friend", "Brother", "Human"]}')
->execute();
$collection
->modify("name = :name")
->bind(['name' => 'Bernie'])
->arrayAppend('traits', 'Happy')
->execute();
$result = $collection
->find()
->execute();
print_r($result->fetchAll());
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[_id] => 00005b6b53610000000000000110
[name] => Bernie
[traits] => Array
(
[0] => Friend
[1] => Brother
[2] => Human
[3] => Happy
)
)
)
CollectionModify::__construct
(No version information available, might only be in Git)
CollectionModify::__construct — CollectionModify constructor
Description
Modify (update) a collection, and is instantiated by the Collection::modify() method.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\CollectionModify::__construct() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$result = $collection
->add(
'{"name": "Bernie",
"traits": ["Friend", "Brother", "Human"]}')
->execute();
$collection
->modify("name in ('Bernie', 'Jane')")
->arrayAppend('traits', 'Happy')
->execute();
$result = $collection
->find()
->execute();
print_r($result->fetchAll());
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[_id] => 00005b6b5361000000000000010c
[name] => Bernie
[traits] => Array
(
[0] => Friend
[1] => Brother
[2] => Human
[3] => Happy
)
)
)
CollectionModify::execute
(No version information available, might only be in Git)
CollectionModify::execute — Execute modify operation
Description
The execute method is required to send the CRUD operation request to the MySQL server.
Parameters
This function has no parameters.
Return Values
A Result object that can be used to verify the status of the operation, such as the number of affected rows.
Examples
Example #1 mysql_xdevapi\CollectionModify::execute() example
<?php
/* ... */
?>
CollectionModify::limit
(No version information available, might only be in Git)
CollectionModify::limit — Limit number of modified documents
Description
Limit the number of documents modified by this operation. Optionally combine with skip() to define an offset value.
Parameters
-
rows -
The maximum number of documents to modify.
Return Values
A CollectionModify object.
Examples
Example #1 mysql_xdevapi\CollectionModify::limit() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$collection->add('{"name": "Fred", "age": 21, "job": "Construction"}')->execute();
$collection->add('{"name": "Wilma", "age": 23, "job": "Teacher"}')->execute();
$collection->add('{"name": "Betty", "age": 24, "job": "Teacher"}')->execute();
$collection
->modify("job = :job")
->bind(['job' => 'Teacher'])
->set('job', 'Principal')
->limit(1)
->execute();
$result = $collection
->find()
->execute();
print_r($result->fetchAll());
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[_id] => 00005b6b53610000000000000118
[age] => 21
[job] => Construction
[name] => Fred
)
[1] => Array
(
[_id] => 00005b6b53610000000000000119
[age] => 23
[job] => Principal
[name] => Wilma
)
[2] => Array
(
[_id] => 00005b6b5361000000000000011a
[age] => 24
[job] => Teacher
[name] => Betty
)
)
CollectionModify::patch
(No version information available, might only be in Git)
CollectionModify::patch — Patch document
Description
Takes a patch object and applies it on one or more documents, and can update multiple document properties.
This function is currently not documented; only its argument list is available.
Parameters
-
document -
A document with the properties to apply to the matching documents.
Return Values
A CollectionModify object.
Examples
Example #1 mysql_xdevapi\CollectionModify::patch() example
<?php
$res = $coll->modify('"Programmatore" IN job')->patch('{"Hobby" : "Programmare"}')->execute();
?>
CollectionModify::replace
(No version information available, might only be in Git)
CollectionModify::replace — Replace document field
Description
$collection_field
, string $expression_or_literal
) : mysql_xdevapi\CollectionModifyReplace (update) a given field value with a new one.
Parameters
-
collection_field -
The document path of the item to set.
-
expression_or_literal -
The value to set on the specified attribute.
Return Values
A CollectionModify object.
Examples
Example #1 mysql_xdevapi\CollectionModify::replace() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$result = $collection
->add(
'{"name": "Bernie",
"traits": ["Friend", "Brother", "Human"]}')
->execute();
$collection
->modify("name = :name")
->bind(['name' => 'Bernie'])
->replace("name", "Bern")
->execute();
$result = $collection
->find()
->execute();
print_r($result->fetchAll());
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[_id] => 00005b6b5361000000000000011b
[name] => Bern
[traits] => Array
(
[0] => Friend
[1] => Brother
[2] => Human
)
)
)
CollectionModify::set
(No version information available, might only be in Git)
CollectionModify::set — Set document attribute
Description
$collection_field
, string $expression_or_literal
) : mysql_xdevapi\CollectionModifySets or updates attributes on documents in a collection.
Parameters
-
collection_field -
The document path (name) of the item to set.
-
expression_or_literal -
The value to set it to.
Return Values
A CollectionModify object.
Examples
Example #1 mysql_xdevapi\CollectionModify::set() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$result = $collection
->add(
'{"name": "Bernie",
"traits": ["Friend", "Brother", "Human"]}')
->execute();
$collection
->modify("name = :name")
->bind(['name' => 'Bernie'])
->set("name", "Bern")
->execute();
$result = $collection
->find()
->execute();
print_r($result->fetchAll());
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[_id] => 00005b6b53610000000000000111
[name] => Bern
[traits] => Array
(
[0] => Friend
[1] => Brother
[2] => Human
)
)
)
CollectionModify::skip
(No version information available, might only be in Git)
CollectionModify::skip — Skip elements
Description
Skip the first N elements that would otherwise be returned by a find operation. If the number of elements skipped is larger than the size of the result set, then the find operation returns an empty set.
This function is currently not documented; only its argument list is available.
Parameters
-
position -
Number of elements to skip.
Return Values
A CollectionModify object to use for further processing.
Examples
Example #1 mysql_xdevapi\CollectionModify::skip() example
<?php
$coll->modify('age > :age')->sort('age desc')->unset(['age'])->bind(['age' => 20])->limit(4)->skip(1)->execute();
?>
CollectionModify::sort
(No version information available, might only be in Git)
CollectionModify::sort — Set the sorting criteria
Description
Sort the result set by the field selected in the sort_expr argument. The allowed orders are ASC (Ascending) or DESC (Descending). This operation is equivalent to the 'ORDER BY' SQL operation and it follows the same set of rules.
This function is currently not documented; only its argument list is available.
Parameters
-
sort_expr -
One or more sorting expression can be provided, the evaluation of these will be from the leftmost to the rightmost, each expression must be separated by a comma.
Return Values
CollectionModify object that can be used for further processing.
Examples
Example #1 mysql_xdevapi\CollectionModify::sort() example
<?php
$res = $coll->modify('true')->sort('name desc', 'age asc')->limit(4)->set('Married', 'NO')->execute();
?>
CollectionModify::unset
(No version information available, might only be in Git)
CollectionModify::unset — Unset the value of document fields
Description
Removes attributes from documents in a collection.
This function is currently not documented; only its argument list is available.
Parameters
-
fields -
The attributes to remove from documents in a collection.
Return Values
CollectionModify object that can be used for further processing.
Examples
Example #1 mysql_xdevapi\CollectionModify::unset() example
<?php
$res = $coll->modify('job like :job_name')->unset(["age", "name"])->bind(['job_name' => 'Plumber'])->execute();
?>
Table of Contents
- CollectionModify::arrayAppend — Append element to an array field
- CollectionModify::arrayInsert — Insert element into an array field
- CollectionModify::bind — Bind value to query placeholder
- CollectionModify::__construct — CollectionModify constructor
- CollectionModify::execute — Execute modify operation
- CollectionModify::limit — Limit number of modified documents
- CollectionModify::patch — Patch document
- CollectionModify::replace — Replace document field
- CollectionModify::set — Set document attribute
- CollectionModify::skip — Skip elements
- CollectionModify::sort — Set the sorting criteria
- CollectionModify::unset — Unset the value of document fields
CollectionRemove class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
CollectionRemove::bind
(No version information available, might only be in Git)
CollectionRemove::bind — Bind value to placeholder
Description
$placeholder_values
) : mysql_xdevapi\CollectionRemoveBind a parameter to the placeholder in the search condition of the remove operation.
The placeholder has the form of :NAME where ':' is a common prefix that must always exists before any NAME where NAME is the name of the placeholder. The bind method accepts a list of placeholders if multiple entities have to be substituted in the search condition of the remove operation.
This function is currently not documented; only its argument list is available.
Parameters
-
placeholder_values -
Placeholder values to substitute in the search condition. Multiple values are allowed and have to be passed as an array of mappings PLACEHOLDER_NAME->PLACEHOLDER_VALUE.
Return Values
A CollectionRemove object that can be used to execute the command, or to add additional operations.
Examples
Example #1 mysql_xdevapi\CollectionRemove::bind() example
<?php
$res = $coll->remove('age > :age_from and age < :age_to')->bind(['age_from' => 20, 'age_to' => 50])->limit(7)->execute();
?>
CollectionRemove::__construct
(No version information available, might only be in Git)
CollectionRemove::__construct — CollectionRemove constructor
Description
Remove collection documents, and is instantiated by the Collection::remove() method.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\Collection::remove() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");
$collection->add('{"name": "Alfred", "age": 18, "job": "Butler"}')->execute();
$collection->add('{"name": "Bob", "age": 19, "job": "Painter"}')->execute();
// Remove all painters
$collection
->remove("job in ('Painter')")
->execute();
// Remove the oldest butler
$collection
->remove("job in ('Butler')")
->sort('age desc')
->limit(1)
->execute();
// Remove record with lowest age
$collection
->remove('true')
->sort('age desc')
->limit(1)
->execute();
?>
CollectionRemove::execute
(No version information available, might only be in Git)
CollectionRemove::execute — Execute remove operation
Description
The execute function needs to be invoked in order to trigger the client to send the CRUD operation request to the server.
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Result object.
Examples
Example #1 mysql_xdevapi\CollectionRemove::execute() example
<?php
$res = $coll->remove('true')->sort('age desc')->limit(2)->execute();
?>
CollectionRemove::limit
(No version information available, might only be in Git)
CollectionRemove::limit — Limit number of documents to remove
Description
Sets the maximum number of documents to remove.
This function is currently not documented; only its argument list is available.
Parameters
-
rows -
The maximum number of documents to remove.
Return Values
Returns a CollectionRemove object that can be used to execute the command, or to add additional operations.
Examples
Example #1 mysql_xdevapi\CollectionRemove::limit() example
<?php
$res = $coll->remove('job in (\'Barista\', \'Programmatore\', \'Ballerino\', \'Programmatrice\')')->limit(5)->sort(['age desc', 'name asc'])->execute();
?>
CollectionRemove::sort
(No version information available, might only be in Git)
CollectionRemove::sort — Set the sorting criteria
Description
Sort the result set by the field selected in the sort_expr argument. The allowed orders are ASC (Ascending) or DESC (Descending). This operation is equivalent to the 'ORDER BY' SQL operation and it follows the same set of rules.
This function is currently not documented; only its argument list is available.
Parameters
-
sort_expr -
One or more sorting expressions can be provided. The evaluation is from left to right, and each expression is separated by a comma.
Return Values
A CollectionRemove object that can be used to execute the command, or to add additional operations.
Examples
Example #1 mysql_xdevapi\CollectionRemove::sort() example
<?php
$res = $coll->remove('true')->sort('age desc')->limit(2)->execute();
?>
Table of Contents
- CollectionRemove::bind — Bind value to placeholder
- CollectionRemove::__construct — CollectionRemove constructor
- CollectionRemove::execute — Execute remove operation
- CollectionRemove::limit — Limit number of documents to remove
- CollectionRemove::sort — Set the sorting criteria
ColumnResult class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
ColumnResult::__construct
(No version information available, might only be in Git)
ColumnResult::__construct — ColumnResult constructor
Description
Retrieve column metadata, such as its character set; this is instantiated by the RowResult::getColumns() method.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\ColumnResult::__construct() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS nonsense")->execute();
$session->sql("CREATE DATABASE nonsense")->execute();
$session->sql("CREATE TABLE nonsense.numbers (hello int, world float unsigned)")->execute();
$session->sql("INSERT INTO nonsense.numbers values (42, 42)")->execute();
$schema = $session->getSchema("nonsense");
$table = $schema->getTable("numbers");
$result1 = $table->select('hello','world')->execute();
// Returns an array of ColumnResult objects
$columns = $result1->getColumns();
foreach ($columns as $column) {
echo "\nColumn label " , $column->getColumnLabel();
echo " is type " , $column->getType();
echo " and is ", ($column->isNumberSigned() === 0) ? "Unsigned." : "Signed.";
}
// Alternatively
$result2 = $session->sql("SELECT * FROM nonsense.numbers")->execute();
// Returns an array of FieldMetadata objects
print_r($result2->getColumns());
The above example will output something similar to:
Column label hello is type 19 and is Signed.
Column label world is type 4 and is Unsigned.
Array
(
[0] => mysql_xdevapi\FieldMetadata Object
(
[type] => 1
[type_name] => SINT
[name] => hello
[original_name] => hello
[table] => numbers
[original_table] => numbers
[schema] => nonsense
[catalog] => def
[collation] => 0
[fractional_digits] => 0
[length] => 11
[flags] => 0
[content_type] => 0
)
[1] => mysql_xdevapi\FieldMetadata Object
(
[type] => 6
[type_name] => FLOAT
[name] => world
[original_name] => world
[table] => numbers
[original_table] => numbers
[schema] => nonsense
[catalog] => def
[collation] => 0
[fractional_digits] => 31
[length] => 12
[flags] => 1
[content_type] => 0
)
)
ColumnResult::getCharacterSetName
(No version information available, might only be in Git)
ColumnResult::getCharacterSetName — Get character set
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\ColumnResult::getCharacterSetName() example
<?php
/* ... */
?>
ColumnResult::getCollationName
(No version information available, might only be in Git)
ColumnResult::getCollationName — Get collation name
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\ColumnResult::getCollationName() example
<?php
/* ... */
?>
ColumnResult::getColumnLabel
(No version information available, might only be in Git)
ColumnResult::getColumnLabel — Get column label
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\ColumnResult::getColumnLabel() example
<?php
/* ... */
?>
ColumnResult::getColumnName
(No version information available, might only be in Git)
ColumnResult::getColumnName — Get column name
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\ColumnResult::getColumnName() example
<?php
/* ... */
?>
ColumnResult::getFractionalDigits
(No version information available, might only be in Git)
ColumnResult::getFractionalDigits — Get fractional digit length
Description
Fetch the number of fractional digits for column.
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\ColumnResult::getFractionalDigits() example
<?php
/* ... */
?>
ColumnResult::getLength
(No version information available, might only be in Git)
ColumnResult::getLength — Get column field length
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\ColumnResult::getLength() example
<?php
/* ... */
?>
ColumnResult::getSchemaName
(No version information available, might only be in Git)
ColumnResult::getSchemaName — Get schema name
Description
Fetch the schema name where the column is stored.
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\ColumnResult::getSchemaName() example
<?php
/* ... */
?>
ColumnResult::getTableLabel
(No version information available, might only be in Git)
ColumnResult::getTableLabel — Get table label
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\ColumnResult::getTableLabel() example
<?php
/* ... */
?>
ColumnResult::getTableName
(No version information available, might only be in Git)
ColumnResult::getTableName — Get table name
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Name of the table for the column.
Examples
Example #1 mysql_xdevapi\ColumnResult::getTableName() example
<?php
/* ... */
?>
ColumnResult::getType
(No version information available, might only be in Git)
ColumnResult::getType — Get column type
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\ColumnResult::getType() example
<?php
/* ... */
?>
ColumnResult::isNumberSigned
(No version information available, might only be in Git)
ColumnResult::isNumberSigned — Check if signed type
Description
Retrieve a table's column information, and is instantiated by the RowResult::getColumns() method.
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
TRUE if a given column as a signed type.
Examples
Example #1 mysql_xdevapi\ColumnResult::isNumberSigned() example
<?php
/* ... */
?>
ColumnResult::isPadded
(No version information available, might only be in Git)
ColumnResult::isPadded — Check if padded
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
TRUE if a given column is padded.
Examples
Example #1 mysql_xdevapi\ColumnResult::isPadded() example
<?php
/* ... */
?>
Table of Contents
- ColumnResult::__construct — ColumnResult constructor
- ColumnResult::getCharacterSetName — Get character set
- ColumnResult::getCollationName — Get collation name
- ColumnResult::getColumnLabel — Get column label
- ColumnResult::getColumnName — Get column name
- ColumnResult::getFractionalDigits — Get fractional digit length
- ColumnResult::getLength — Get column field length
- ColumnResult::getSchemaName — Get schema name
- ColumnResult::getTableLabel — Get table label
- ColumnResult::getTableName — Get table name
- ColumnResult::getType — Get column type
- ColumnResult::isNumberSigned — Check if signed type
- ColumnResult::isPadded — Check if padded
CrudOperationBindable interface
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
CrudOperationBindable::bind
(No version information available, might only be in Git)
CrudOperationBindable::bind — Bind value to placeholder
Description
$placeholder_values
) : mysql_xdevapi\CrudOperationBindableBinds a value to a specific placeholder.
This function is currently not documented; only its argument list is available.
Parameters
-
placeholder_values -
The name of the placeholders and the values to bind.
Return Values
A CrudOperationBindable object.
Examples
Example #1 mysql_xdevapi\CrudOperationBindable::bind() example
<?php
$res = $coll->modify('name like :name')->arrayInsert('job[0]', 'Calciatore')->bind(['name' => 'ENTITY'])->execute();
$res = $table->delete()->orderby('age desc')->where('age < 20 and age > 12 and name != :name')->bind(['name' => 'Tierney'])->limit(2)->execute();
?>
Table of Contents
- CrudOperationBindable::bind — Bind value to placeholder
CrudOperationLimitable interface
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
CrudOperationLimitable::limit
(No version information available, might only be in Git)
CrudOperationLimitable::limit — Set result limit
Description
$rows
) : mysql_xdevapi\CrudOperationLimitableSets the maximum number of records or documents to return.
This function is currently not documented; only its argument list is available.
Parameters
-
rows -
The maximum number of records or documents.
Return Values
A CrudOperationLimitable object.
Examples
Example #1 mysql_xdevapi\CrudOperationLimitable::limit() example
<?php
$res = $coll->find()->fields(['name as n','age as a','job as j'])->groupBy('j')->limit(11)->execute();
$res = $table->update()->set('age',69)->where('age > 15 and age < 22')->limit(4)->orderby(['age asc','name desc'])->execute();
?>
Table of Contents
- CrudOperationLimitable::limit — Set result limit
CrudOperationSkippable interface
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
CrudOperationSkippable::skip
(No version information available, might only be in Git)
CrudOperationSkippable::skip — Number of operations to skip
Description
$skip
) : mysql_xdevapi\CrudOperationSkippableSkip this number of records in the returned operation.
This function is currently not documented; only its argument list is available.
Parameters
-
skip -
Number of elements to skip.
Return Values
A CrudOperationSkippable object.
Examples
Example #1 mysql_xdevapi\CrudOperationSkippable::skip() example
<?php
$res = $coll->find('job like \'Programmatore\'')->limit(1)->skip(3)->sort('age asc')->execute();
?>
Table of Contents
- CrudOperationSkippable::skip — Number of operations to skip
CrudOperationSortable interface
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
CrudOperationSortable::sort
(No version information available, might only be in Git)
CrudOperationSortable::sort — Sort results
Description
$sort_expr
) : mysql_xdevapi\CrudOperationSortableSort the result set by the field selected in the sort_expr argument. The allowed orders are ASC (Ascending) or DESC (Descending). This operation is equivalent to the 'ORDER BY' SQL operation and it follows the same set of rules.
This function is currently not documented; only its argument list is available.
Parameters
-
sort_expr -
One or more sorting expressions can be provided. The evaluation is from left to right, and each expression is separated by a comma.
Return Values
A CrudOperationSortable object.
Examples
Example #1 mysql_xdevapi\CrudOperationSortable::sort() example
<?php
$res = $coll->find('job like \'Cavia\'')->sort('age desc', '_id desc')->execute();
?>
Table of Contents
- CrudOperationSortable::sort — Sort results
DatabaseObject interface
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
DatabaseObject::existsInDatabase
(No version information available, might only be in Git)
DatabaseObject::existsInDatabase — Check if object exists in database
Description
Verifies if the database object refers to an object that exists in the database.
Parameters
This function has no parameters.
Return Values
Returns TRUE if object exists in the database, else FALSE if it does not.
Examples
Example #1 mysql_xdevapi\DatabaseObject::existsInDatabase() example
<?php
$existInDb = $dbObj->existsInDatabase();
?>
DatabaseObject::getName
(No version information available, might only be in Git)
DatabaseObject::getName — Get object name
Description
Fetch name of this database object.
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
The name of this database object.
Examples
Example #1 mysql_xdevapi\DatabaseObject::getName() example
<?php
$dbObjName = $dbObj->getName();
?>
DatabaseObject::getSession
(No version information available, might only be in Git)
DatabaseObject::getSession — Get session name
Description
Fetch session associated to the database object.
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
The Session object.
Examples
Example #1 mysql_xdevapi\DatabaseObject::getSession() example
<?php
$session = $dbObj->getSession();
?>
Table of Contents
- DatabaseObject::existsInDatabase — Check if object exists in database
- DatabaseObject::getName — Get object name
- DatabaseObject::getSession — Get session name
DocResult class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
DocResult::__construct
(No version information available, might only be in Git)
DocResult::__construct — DocResult constructor
Description
Fetch document results and warnings, and is instantiated by CollectionFind.
Parameters
This function has no parameters.
Examples
Example #1 A DocResult example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$create->add('{"name": "Alfred", "age": 18, "job": "Butler"}')->execute();
$create->add('{"name": "Reginald", "age": 42, "job": "Butler"}')->execute();
// ...
$collection = $schema->getCollection("people");
// Yields a DocResult object
$result = $collection
->find('job like :job and age > :age')
->bind(['job' => 'Butler', 'age' => 16])
->sort('age desc')
->limit(1)
->execute();
var_dump($result->fetchAll());
?>
The above example will output something similar to:
array(1) {
[0]=>
array(4) {
["_id"]=>
string(28) "00005b6b536100000000000000f3"
["age"]=>
int(42)
["job"]=>
string(6) "Butler"
["name"]=>
string(8) "Reginald"
}
}
DocResult::fetchAll
(No version information available, might only be in Git)
DocResult::fetchAll — Get all rows
Description
Fetch all results from a result set.
Parameters
This function has no parameters.
Return Values
A numerical array with all results from the query; each result is an associative array. An empty array is returned if no rows are present.
Examples
Example #1 mysql_xdevapi\DocResult::fetchAll() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$create->add('{"name": "Alfred", "age": 18, "job": "Butler"}')->execute();
$create->add('{"name": "Reginald", "age": 42, "job": "Butler"}')->execute();
// ...
$collection = $schema->getCollection("people");
// Yields a DocResult object
$result = $collection
->find('job like :job and age > :age')
->bind(['job' => 'Butler', 'age' => 16])
->sort('age desc')
->execute();
var_dump($result->fetchAll());
?>
The above example will output something similar to:
array(2) {
[0]=>
array(4) {
["_id"]=>
string(28) "00005b6b53610000000000000123"
["age"]=>
int(42)
["job"]=>
string(6) "Butler"
["name"]=>
string(8) "Reginald"
}
[1]=>
array(4) {
["_id"]=>
string(28) "00005b6b53610000000000000122"
["age"]=>
int(18)
["job"]=>
string(6) "Butler"
["name"]=>
string(6) "Alfred"
}
}
DocResult::fetchOne
(No version information available, might only be in Git)
DocResult::fetchOne — Get one row
Description
Fetch one result from a result set.
Parameters
This function has no parameters.
Return Values
The result, as an associative array
or NULL if no results are present.
Examples
Example #1 mysql_xdevapi\DocResult::fetchOne() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$create->add('{"name": "Alfred", "age": 18, "job": "Butler"}')->execute();
$create->add('{"name": "Reginald", "age": 42, "job": "Butler"}')->execute();
// ...
$collection = $schema->getCollection("people");
// Yields a DocResult object
$result = $collection
->find('job like :job and age > :age')
->bind(['job' => 'Butler', 'age' => 16])
->sort('age desc')
->execute();
var_dump($result->fetchOne());
?>
The above example will output something similar to:
array(4) {
["_id"]=>
string(28) "00005b6b53610000000000000125"
["age"]=>
int(42)
["job"]=>
string(6) "Butler"
["name"]=>
string(8) "Reginald"
}
DocResult::getWarnings
(No version information available, might only be in Git)
DocResult::getWarnings — Get warnings from last operation
Description
Fetches warnings generated by MySQL server's last operation.
Parameters
This function has no parameters.
Return Values
An array of Warning objects from the last operation. Each object defines an error 'message', error 'level', and error 'code'. An empty array is returned if no errors are present.
Examples
Example #1 mysql_xdevapi\DocResult::getWarnings() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$create->add('{"name": "Alfred", "age": 18, "job": "Butler"}')->execute();
$create->add('{"name": "Reginald", "age": 42, "job": "Butler"}')->execute();
// ...
$collection = $schema->getCollection("people");
// Yields a DocResult object
$result = $collection
->find('job like :job and age > :age')
->bind(['job' => 'Butler', 'age' => 16])
->sort('age desc')
->execute();
if (!$result->getWarningsCount()) {
echo "There was an error:\n";
print_r($result->getWarnings());
exit;
}
var_dump($result->fetchOne());
?>
The above example will output something similar to:
There was an error:
Array
(
[0] => mysql_xdevapi\Warning Object
(
[message] => Something bad and so on
[level] => 2
[code] => 1365
)
[1] => mysql_xdevapi\Warning Object
(
[message] => Something bad and so on
[level] => 2
[code] => 1365
)
)
DocResult::getWarningsCount
(No version information available, might only be in Git)
DocResult::getWarningsCount — Get warning count from last operation
Description
Returns the number of warnings raised by the last operation. Specifically, these warnings are raised by the MySQL server.
Parameters
This function has no parameters.
Return Values
The number of warnings from the last operation.
Examples
Example #1 mysql_xdevapi\DocResult::getWarningsCount() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$create->add('{"name": "Alfred", "age": 18, "job": "Butler"}')->execute();
$create->add('{"name": "Reginald", "age": 42, "job": "Butler"}')->execute();
// ...
$collection = $schema->getCollection("people");
// Yields a DocResult object
$result = $collection
->find('job like :job and age > :age')
->bind(['job' => 'Butler', 'age' => 16])
->sort('age desc')
->execute();
if (!$result->getWarningsCount()) {
echo "There was an error:\n";
print_r($result->getWarnings());
exit;
}
var_dump($result->fetchOne());
?>
The above example will output something similar to:
array(4) {
["_id"]=>
string(28) "00005b6b53610000000000000135"
["age"]=>
int(42)
["job"]=>
string(6) "Butler"
["name"]=>
string(8) "Reginald"
}
Table of Contents
- DocResult::__construct — DocResult constructor
- DocResult::fetchAll — Get all rows
- DocResult::fetchOne — Get one row
- DocResult::getWarnings — Get warnings from last operation
- DocResult::getWarningsCount — Get warning count from last operation
Exception class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
Executable interface
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
Executable::execute
(No version information available, might only be in Git)
Executable::execute — Execute statement
Description
Execute the statement from either a collection operation or a table query; this functionality allows for method chaining.
Parameters
This function has no parameters.
Return Values
One of the Result objects, such as Result or SqlStatementResult.
Examples
Example #1 execute() examples
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$result_sql = $session->sql("CREATE DATABASE addressbook")->execute();
var_dump($result_sql);
$schema = $session->getSchema("addressbook");
$collection = $schema->createCollection("humans");
$result_collection = $collection->add(
'{"name": "Jane",
"jobs": [{"title":"Scientist","Salary":18000}, {"title":"Mother","Salary":0}],
"hobbies": ["Walking","Making pies"]}');
$result_collection_executed = $result_collection->execute();
var_dump($result_collection);
var_dump($result_collection_executed);
?>
The above example will output something similar to:
object(mysql_xdevapi\SqlStatementResult)#3 (0) {
}
object(mysql_xdevapi\CollectionAdd)#5 (0) {
}
object(mysql_xdevapi\Result)#7 (0) {
}
Table of Contents
- Executable::execute — Execute statement
ExecutionStatus class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
Properties
- affectedItems
- matchedItems
- foundItems
- lastInsertId
- lastDocumentId
ExecutionStatus::__construct
(No version information available, might only be in Git)
ExecutionStatus::__construct — ExecutionStatus constructor
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\ExecutionStatus::__construct() example
<?php
/* ... */
?>
Table of Contents
- ExecutionStatus::__construct — ExecutionStatus constructor
Expression class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
$expression
)Properties
- name
Expression::__construct
(No version information available, might only be in Git)
Expression::__construct — Expression constructor
Description
$expression
)
This function is currently not documented; only its argument list is available.
Parameters
-
expression -
Examples
Example #1 mysql_xdevapi\Expression::__construct() example
<?php
/* ... */
?>
Table of Contents
- Expression::__construct — Expression constructor
Result class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
Result::__construct
(No version information available, might only be in Git)
Result::__construct — Result constructor
Description
An object that retrieves generated IDs, AUTO_INCREMENT values, and warnings, for a Result set.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\Result::__construct() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("
CREATE TABLE addressbook.names
(id INT NOT NULL AUTO_INCREMENT, name VARCHAR(30), age INT, PRIMARY KEY (id))
")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$result = $table->insert("name", "age")->values(["Suzanne", 31],["Julie", 43])->execute();
$result = $table->insert("name", "age")->values(["Suki", 34])->execute();
$ai = $result->getAutoIncrementValue();
var_dump($ai);
?>
The above example will output:
int(3)
Result::getAffectedItemsCount
(No version information available, might only be in Git)
Result::getAffectedItemsCount — Get affected row count
Description
Get the number of affected rows by the previous operation.
Parameters
This function has no parameters.
Return Values
The number (as an integer) of affected rows.
Examples
Example #1 mysql_xdevapi\Result::getAffectedItemsCount() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$collection = $schema->getCollection("people");
$result = $collection->add('{"name": "Wilma", "age": 23, "job": "Teacher"}')->execute();
var_dump( $res->getAffectedItemsCount() );
?>
The above example will output:
int(1)
Result::getAutoIncrementValue
(No version information available, might only be in Git)
Result::getAutoIncrementValue — Get autoincremented value
Description
Get the last AUTO_INCREMENT value (last insert id).
Parameters
This function has no parameters.
Return Values
The last AUTO_INCREMENT value.
Examples
Example #1 mysql_xdevapi\Result::getAutoIncrementValue() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("
CREATE TABLE addressbook.names
(id INT NOT NULL AUTO_INCREMENT, name VARCHAR(30), age INT, PRIMARY KEY (id))
")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$result = $table->insert("name", "age")->values(["Suzanne", 31],["Julie", 43])->execute();
$result = $table->insert("name", "age")->values(["Suki", 34])->execute();
$ai = $result->getAutoIncrementValue();
var_dump($ai);
?>
The above example will output:
int(3)
Result::getGeneratedIds
(No version information available, might only be in Git)
Result::getGeneratedIds — Get generated ids
Description
Fetch the generated _id values from the last operation. The unique _id field is generated by the MySQL server.
Parameters
This function has no parameters.
Return Values
An array of generated _id's from the last operation, or an empty array if there are none.
Examples
Example #1 mysql_xdevapi\Result::getGeneratedIds() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$create = $schema->createCollection("people");
$collection = $schema->getCollection("people");
$result = $collection->add(
'{"name": "Bernie",
"jobs": [{"title":"Cat Herder","Salary":42000}, {"title":"Father","Salary":0}],
"hobbies": ["Sports","Making cupcakes"]}',
'{"name": "Jane",
"jobs": [{"title":"Scientist","Salary":18000}, {"title":"Mother","Salary":0}],
"hobbies": ["Walking","Making pies"]}')->execute();
$ids = $result->getGeneratedIds();
var_dump($ids);
?>
The above example will output something similar to:
array(2) {
[0]=>
string(28) "00005b6b53610000000000000064"
[1]=>
string(28) "00005b6b53610000000000000065"
}
Result::getWarnings
(No version information available, might only be in Git)
Result::getWarnings — Get warnings from last operation
Description
Retrieve warnings from the last Result operation.
Parameters
This function has no parameters.
Return Values
An array of Warning objects from the last operation. Each object defines an error 'message', error 'level', and error 'code'. An empty array is returned if no errors are present.
Examples
Example #1 mysql_xdevapi\RowResult::getWarnings() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("CREATE DATABASE foo")->execute();
$session->sql("CREATE TABLE foo.test_table(x int)")->execute();
$schema = $session->getSchema("foo");
$table = $schema->getTable("test_table");
$table->insert(['x'])->values([1])->values([2])->execute();
$res = $table->select(['x/0 as bad_x'])->execute();
$warnings = $res->getWarnings();
print_r($warnings);
?>
The above example will output something similar to:
Array
(
[0] => mysql_xdevapi\Warning Object
(
[message] => Division by 0
[level] => 2
[code] => 1365
)
[1] => mysql_xdevapi\Warning Object
(
[message] => Division by 0
[level] => 2
[code] => 1365
)
)
Result::getWarningsCount
(No version information available, might only be in Git)
Result::getWarningsCount — Get warning count from last operation
Description
Retrieve the number of warnings from the last Result operation.
Parameters
This function has no parameters.
Return Values
The number of warnings generated by the last operation.
Examples
Example #1 mysql_xdevapi\RowResult::getWarningsCount() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS foo")->execute();
$session->sql("CREATE DATABASE foo")->execute();
$session->sql("CREATE TABLE foo.test_table(x int)")->execute();
$schema = $session->getSchema("foo");
$table = $schema->getTable("test_table");
$table->insert(['x'])->values([1])->values([2])->execute();
$res = $table->select(['x/0 as bad_x'])->execute();
echo $res->getWarningsCount();
?>
The above example will output something similar to:
2
Table of Contents
- Result::__construct — Result constructor
- Result::getAffectedItemsCount — Get affected row count
- Result::getAutoIncrementValue — Get autoincremented value
- Result::getGeneratedIds — Get generated ids
- Result::getWarnings — Get warnings from last operation
- Result::getWarningsCount — Get warning count from last operation
RowResult class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
RowResult::__construct
(No version information available, might only be in Git)
RowResult::__construct — RowResult constructor
Description
Represents the result set obtained from querying the database.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\RowResult::__construct() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$row = $table->select('name', 'age')->where('age > 18')->execute()->fetchAll();
print_r($row);
The above example will output something similar to:
Array
(
[0] => Array
(
[name] => John
[age] => 42
)
[1] => Array
(
[name] => Sam
[age] => 33
)
)
RowResult::fetchAll
(No version information available, might only be in Git)
RowResult::fetchAll — Get all rows from result
Description
Fetch all the rows from the result set.
Parameters
This function has no parameters.
Return Values
A numerical array with all results from the query; each result is an associative array. An empty array is returned if no rows are present.
Examples
Example #1 mysql_xdevapi\RowResult::fetchAll() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$row = $table->select('name', 'age')->execute()->fetchAll();
print_r($row);
The above example will output something similar to:
Array
(
[0] => Array
(
[name] => John
[age] => 42
)
[1] => Array
(
[name] => Sam
[age] => 33
)
)
RowResult::fetchOne
(No version information available, might only be in Git)
RowResult::fetchOne — Get row from result
Description
Fetch one result from the result set.
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
The result, as an associative array
or NULL if no results are present.
Examples
Example #1 mysql_xdevapi\RowResult::fetchOne() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$row = $table->select('name', 'age')->where('age < 40')->execute()->fetchOne();
print_r($row);
The above example will output something similar to:
Array
(
[name] => Sam
[age] => 33
)
RowResult::getColumnsCount
(No version information available, might only be in Git)
RowResult::getColumnsCount — Get column count
Description
Retrieve the column count for columns present in the result set.
Parameters
This function has no parameters.
Return Values
The number of columns; 0 if there are none.
Changelog
| Version | Description |
|---|---|
| 8.0.14 | Method renamed from getColumnCount() to getColumnsCount(). |
Examples
Example #1 mysql_xdevapi\RowResult::getColumnsCount() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE addressbook")->execute();
$session->sql("CREATE DATABASE foo")->execute();
$session->sql("CREATE TABLE foo.test_table(x int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$sql = $session->sql("SELECT * from addressbook.names")->execute();
echo $sql->getColumnsCount();
The above example will output something similar to:
2
RowResult::getColumnNames
(No version information available, might only be in Git)
RowResult::getColumnNames — Get all column names
Description
Retrieve column names for columns present in the result set.
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
A numerical array of table columns names, or an empty array if the result set is empty.
Examples
Example #1 mysql_xdevapi\RowResult::getColumnNames() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE addressbook")->execute();
$session->sql("CREATE DATABASE foo")->execute();
$session->sql("CREATE TABLE foo.test_table(x int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$sql = $session->sql("SELECT * from addressbook.names")->execute();
$colnames = $sql->getColumnNames();
print_r($colnames);
The above example will output something similar to:
Array
(
[0] => name
[1] => age
)
RowResult::getColumns
(No version information available, might only be in Git)
RowResult::getColumns — Get column metadata
Description
Retrieve column metadata for columns present in the result set.
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
An array of FieldMetadata objects representing the columns in the result, or an empty array if the result set is empty.
Examples
Example #1 mysql_xdevapi\RowResult::getColumns() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE addressbook")->execute();
$session->sql("CREATE DATABASE foo")->execute();
$session->sql("CREATE TABLE foo.test_table(x int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$sql = $session->sql("SELECT * from addressbook.names")->execute();
$cols = $sql->getColumns();
print_r($cols);
The above example will output something similar to:
Array
(
[0] => mysql_xdevapi\FieldMetadata Object
(
[type] => 7
[type_name] => BYTES
[name] => name
[original_name] => name
[table] => names
[original_table] => names
[schema] => addressbook
[catalog] => def
[collation] => 255
[fractional_digits] => 0
[length] => 65535
[flags] => 0
[content_type] => 0
)
[1] => mysql_xdevapi\FieldMetadata Object
(
[type] => 1
[type_name] => SINT
[name] => age
[original_name] => age
[table] => names
[original_table] => names
[schema] => addressbook
[catalog] => def
[collation] => 0
[fractional_digits] => 0
[length] => 11
[flags] => 0
[content_type] => 0
)
)
RowResult::getWarnings
(No version information available, might only be in Git)
RowResult::getWarnings — Get warnings from last operation
Description
Retrieve warnings from the last RowResult operation.
Parameters
This function has no parameters.
Return Values
An array of Warning objects from the last operation. Each object defines an error 'message', error 'level', and error 'code'. An empty array is returned if no errors are present.
Examples
Example #1 mysql_xdevapi\RowResult::getWarnings() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("CREATE DATABASE foo")->execute();
$session->sql("CREATE TABLE foo.test_table(x int)")->execute();
$schema = $session->getSchema("foo");
$table = $schema->getTable("test_table");
$table->insert(['x'])->values([1])->values([2])->execute();
$res = $table->select(['x/0 as bad_x'])->execute();
$warnings = $res->getWarnings();
print_r($warnings);
?>
The above example will output something similar to:
Array
(
[0] => mysql_xdevapi\Warning Object
(
[message] => Division by 0
[level] => 2
[code] => 1365
)
[1] => mysql_xdevapi\Warning Object
(
[message] => Division by 0
[level] => 2
[code] => 1365
)
)
RowResult::getWarningsCount
(No version information available, might only be in Git)
RowResult::getWarningsCount — Get warning count from last operation
Description
Retrieve the number of warnings from the last RowResult operation.
Parameters
This function has no parameters.
Return Values
The number of warnings generated by the last operation.
Examples
Example #1 mysql_xdevapi\RowResult::getWarningsCount() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS foo")->execute();
$session->sql("CREATE DATABASE foo")->execute();
$session->sql("CREATE TABLE foo.test_table(x int)")->execute();
$schema = $session->getSchema("foo");
$table = $schema->getTable("test_table");
$table->insert(['x'])->values([1])->values([2])->execute();
$res = $table->select(['x/0 as bad_x'])->execute();
echo $res->getWarningsCount();
?>
The above example will output something similar to:
2
Table of Contents
- RowResult::__construct — RowResult constructor
- RowResult::fetchAll — Get all rows from result
- RowResult::fetchOne — Get row from result
- RowResult::getColumnsCount — Get column count
- RowResult::getColumnNames — Get all column names
- RowResult::getColumns — Get column metadata
- RowResult::getWarnings — Get warnings from last operation
- RowResult::getWarningsCount — Get warning count from last operation
Schema class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
$collection_name
) : boolProperties
- name
Schema::__construct
(No version information available, might only be in Git)
Schema::__construct — constructor
Description
The Schema object provides full access to the schema (database).
Parameters
This function has no parameters.
Examples
Example #1 Schema::__construct example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS food")->execute();
$session->sql("CREATE DATABASE food")->execute();
$session->sql("CREATE TABLE food.fruit(name text, rating text)")->execute();
$schema = $session->getSchema("food");
$schema->createCollection("trees");
print_r($schema->gettables());
print_r($schema->getcollections());
The above example will output something similar to:
Array
(
[fruit] => mysql_xdevapi\Table Object
(
[name] => fruit
)
)
Array
(
[trees] => mysql_xdevapi\Collection Object
(
[name] => trees
)
)
Schema::createCollection
(No version information available, might only be in Git)
Schema::createCollection — Add collection to schema
Description
Create a collection within the schema.
This function is currently not documented; only its argument list is available.
Parameters
-
name -
Return Values
Examples
Example #1 Schema::createCollection example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS food")->execute();
$session->sql("CREATE DATABASE food")->execute();
$session->sql("CREATE TABLE food.fruit(name text, rating text)")->execute();
$schema = $session->getSchema("food");
$schema->createCollection("trees");
print_r($schema->gettables());
print_r($schema->getcollections());
The above example will output something similar to:
Array
(
[fruit] => mysql_xdevapi\Table Object
(
[name] => fruit
)
)
Array
(
[trees] => mysql_xdevapi\Collection Object
(
[name] => trees
)
)
Schema::dropCollection
(No version information available, might only be in Git)
Schema::dropCollection — Drop collection from schema
Description
$collection_name
) : bool
This function is currently not documented; only its argument list is available.
Parameters
-
collection_name -
Return Values
Examples
Example #1 Schema::dropCollection example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS food")->execute();
$session->sql("CREATE DATABASE food")->execute();
$session->sql("CREATE TABLE food.fruit(name text, rating text)")->execute();
$schema = $session->getSchema("food");
$schema->createCollection("trees");
$schema->dropCollection("trees");
$schema->createCollection("buildings");
print_r($schema->gettables());
print_r($schema->getcollections());
The above example will output something similar to:
Array
(
[fruit] => mysql_xdevapi\Table Object
(
[name] => fruit
)
)
Array
(
[buildings] => mysql_xdevapi\Collection Object
(
[name] => buildings
)
)
Schema::existsInDatabase
(No version information available, might only be in Git)
Schema::existsInDatabase — Check if exists in database
Description
Checks if the current object (schema, table, collection, or view) exists in the schema object.
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
TRUE if the schema, table, collection, or view still exists in the schema, else FALSE.
Examples
Example #1 Schema::existsInDatabase example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS food")->execute();
$session->sql("CREATE DATABASE food")->execute();
$session->sql("CREATE TABLE food.fruit(name text, rating text)")->execute();
$schema = $session->getSchema("food");
$schema->createCollection("trees");
// ...
$trees = $schema->getCollection("trees");
// ...
// Is this collection still in the database (schema)?
if ($trees->existsInDatabase()) {
echo "Yes, the 'trees' collection is still present.";
}
The above example will output something similar to:
Yes, the 'trees' collection is still present.
Schema::getCollection
(No version information available, might only be in Git)
Schema::getCollection — Get collection from schema
Description
Get a collection from the schema.
Parameters
-
name -
Collection name to retrieve.
Return Values
The Collection object for the selected collection.
Examples
Example #1 Schema::getCollection example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS food")->execute();
$session->sql("CREATE DATABASE food")->execute();
$schema = $session->getSchema("food");
$schema->createCollection("trees");
// ...
$trees = $schema->getCollection("trees");
var_dump($trees);
The above example will output something similar to:
object(mysql_xdevapi\Collection)#3 (1) {
["name"]=>
string(5) "trees"
}
Schema::getCollectionAsTable
(No version information available, might only be in Git)
Schema::getCollectionAsTable — Get collection table object
Description
Get a collection, but as a Table object instead of a Collection object.
Parameters
-
name -
Name of the collection to instantiate a Table object from.
Return Values
A table object for the collection.
Examples
Example #1 Schema::getCollectionAsTable example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collect = $schema->createCollection("people");
$collect->add('{"name": "Fred", "age": 21, "job": "Construction"}')->execute();
$collect->add('{"name": "Wilma", "age": 23, "job": "Teacher"}')->execute();
$table = $schema->getCollectionAsTable("people");
$collection = $schema->getCollection("people");
var_dump($table);
var_dump($collection);
The above example will output something similar to:
object(mysql_xdevapi\Table)#4 (1) {
["name"]=>
string(6) "people"
}
object(mysql_xdevapi\Collection)#5 (1) {
["name"]=>
string(6) "people"
}
Schema::getCollections
(No version information available, might only be in Git)
Schema::getCollections — Get all schema collections
Description
Fetch a list of collections for this schema.
Parameters
This function has no parameters.
Return Values
Array of all collections in this schema, where each array element value is a Collection object with the collection name as the key.
Examples
Example #1 mysql_xdevapi\Schema::getCollections() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
$collect = $schema->createCollection("people");
$collect->add('{"name": "Fred", "age": 21, "job": "Construction"}')->execute();
$collect->add('{"name": "Wilma", "age": 23, "job": "Teacher"}')->execute();
$collections = $schema->getCollections();
var_dump($collections);
?>
The above example will output something similar to:
array(1) {
["people"]=>
object(mysql_xdevapi\Collection)#4 (1) {
["name"]=>
string(6) "people"
}
}
Schema::getName
(No version information available, might only be in Git)
Schema::getName — Get schema name
Description
Get the name of the schema.
Parameters
This function has no parameters.
Return Values
The name of the schema connected to the schema object, as a string.
Examples
Example #1 mysql_xdevapi\Schema::getName() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
// ...
var_dump($schema->getName());
?>
The above example will output something similar to:
string(11) "addressbook"
Schema::getSession
(No version information available, might only be in Git)
Schema::getSession — Get schema session
Description
Get a new Session object from the Schema object.
Parameters
This function has no parameters.
Return Values
A Session object.
Examples
Example #1 mysql_xdevapi\Schema::getSession() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$schema = $session->getSchema("addressbook");
// ...
$newsession = $schema->getSession();
var_dump($session);
var_dump($newsession);
?>
The above example will output something similar to:
object(mysql_xdevapi\Session)#1 (0) {
}
object(mysql_xdevapi\Session)#3 (0) {
}
Schema::getTable
(No version information available, might only be in Git)
Schema::getTable — Get schema table
Description
Fetch a Table object for the provided table in the schema.
Parameters
-
name -
Name of the table.
Return Values
A Table object.
Examples
Example #1 mysql_xdevapi\Schema::getTable() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$row = $table->select('name', 'age')->execute()->fetchAll();
print_r($row);
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[name] => John
[age] => 42
)
[1] => Array
(
[name] => Sam
[age] => 33
)
)
Schema::getTables
(No version information available, might only be in Git)
Schema::getTables — Get schema tables
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Array of all tables in this schema, where each array element value is a Table object with the table name as the key.
Examples
Example #1 mysql_xdevapi\Schema::getTables() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$session->sql("CREATE TABLE addressbook.cities(name text, population int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('Portland', 639863), ('Seattle', 704352)")->execute();
$schema = $session->getSchema("addressbook");
$tables = $schema->getTables();
var_dump($tables);
?>
The above example will output something similar to:
array(2) {
["cities"]=>
object(mysql_xdevapi\Table)#3 (1) {
["name"]=>
string(6) "cities"
}
["names"]=>
object(mysql_xdevapi\Table)#4 (1) {
["name"]=>
string(5) "names"
}
}
Table of Contents
- Schema::__construct — constructor
- Schema::createCollection — Add collection to schema
- Schema::dropCollection — Drop collection from schema
- Schema::existsInDatabase — Check if exists in database
- Schema::getCollection — Get collection from schema
- Schema::getCollectionAsTable — Get collection table object
- Schema::getCollections — Get all schema collections
- Schema::getName — Get schema name
- Schema::getSession — Get schema session
- Schema::getTable — Get schema table
- Schema::getTables — Get schema tables
SchemaObject interface
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
SchemaObject::getSchema
(No version information available, might only be in Git)
SchemaObject::getSchema — Get schema object
Description
Used by other objects to retrieve a schema object.
Parameters
This function has no parameters.
Return Values
The current Schema object.
Examples
Example #1 mysql_xdevapi\Session::getSchema() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
print_r($schema);
The above example will output something similar to:
mysql_xdevapi\Schema Object
(
[name] => addressbook
)
Table of Contents
- SchemaObject::getSchema — Get schema object
Session class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
$schema_name
) : bool$name
) : string$name
) : void$name
) : void$name
] ) : stringSession::close
(No version information available, might only be in Git)
Session::close — Close session
Description
Close the session with the server.
Parameters
This function has no parameters.
Return Values
TRUE if the session closed.
Examples
Example #1 mysql_xdevapi\Session::close() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$session->close();
Session::commit
(PHP 4 >= 4.4.0, PHP 5, PHP 7)
Session::commit — Commit transaction
Description
Commit the transaction.
Parameters
This function has no parameters.
Return Values
An SqlStatementResult object.
Examples
Example #1 mysql_xdevapi\Session::commit() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$collection = $session->getSchema("addressbook")->getCollection("friends");
$session->startTransaction();
$collection->add('{"John":42, "Sam":33}')->execute();
$savepoint = $session->setSavepoint();
$session->commit();
$session->close();
Session::__construct
(No version information available, might only be in Git)
Session::__construct — Description constructor
Description
A Session object, as initiated by getSession().
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\Session::__construct() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->close();
?>
Session::createSchema
(No version information available, might only be in Git)
Session::createSchema — Create new schema
Description
Creates a new schema.
Parameters
-
schema_name -
Name of the schema to create.
Return Values
A Schema object on success, and emits an exception on failure.
Examples
Example #1 mysql_xdevapi\Session::createSchema() example
<?php
$uri = 'mysqlx://happyuser:password@127.0.0.1:33060/';
$sess = mysql_xdevapi\getSession($uri);
try {
if ($schema = $sess->createSchema('fruit')) {
echo "Info: I created a schema named 'fruit'\n";
}
} catch (Exception $e) {
echo $e->getMessage();
}
?>
The above example will output something similar to:
Info: I created a schema named 'fruit'
Session::dropSchema
(No version information available, might only be in Git)
Session::dropSchema — Drop a schema
Description
$schema_name
) : boolDrop a schema (database).
Parameters
-
schema_name -
Name of the schema to drop.
Return Values
TRUE if the schema is dropped, or FALSE if it does not exist
or can't be dropped.
An E_WARNING level error is generated if the
schema does not exist.
Examples
Example #1 mysql_xdevapi\Session::dropSchema() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->dropSchema("addressbook");
$session->close();
?>
Session::generateUUID
(No version information available, might only be in Git)
Session::generateUUID — Get new UUID
Description
Generate a Universal Unique IDentifier (UUID) generated according to » RFC 4122.
Parameters
This function has no parameters.
Return Values
The UUID; a string with a length of 32.
Examples
Example #1 mysql_xdevapi\Session::generateUuid() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$uuid = $session->generateUuid();
var_dump($uuid);
The above example will output something similar to:
string(32) "484B18AC7980F8D4FE84613CDA5EE84B"
Session::getDefaultSchema
(No version information available, might only be in Git)
Session::getDefaultSchema — Get default schema name
Description
Retrieve name of the default schema that's typically set in the connection URI.
Parameters
This function has no parameters.
Return Values
Name of the default schema defined by the connection, or NULL if
one was not set.
Examples
Example #1 mysql_xdevapi\Session::getSchema() example
<?php
$uri = "mysqlx://testuser:testpasswd@localhost:33160/testx?ssl-mode=disabled";
$session = mysql_xdevapi\getSession($uri);
$schema = $session->getDefaultSchema();
echo $schema;
?>
The above example will output:
testx
Session::getSchema
(No version information available, might only be in Git)
Session::getSchema — Get a new schema object
Description
A new Schema object for the provided schema name.
Parameters
-
schema_name -
Name of the schema (database) to fetch a Schema object for.
Return Values
A Schema object.
Examples
Example #1 mysql_xdevapi\Session::getSchema() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
print_r($schema);
The above example will output something similar to:
mysql_xdevapi\Schema Object
(
[name] => addressbook
)
Session::getSchemas
(No version information available, might only be in Git)
Session::getSchemas — Get the schemas
Description
Get schema objects for all schemas available to the session.
Parameters
This function has no parameters.
Return Values
An array containing objects that represent all of the schemas available to the session.
Examples
Example #1 mysql_xdevapi\Session::getSchemas() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schemas = $session->getSchemas();
print_r($schemas);
The above example will output something similar to:
Array
(
[0] => mysql_xdevapi\Schema Object
(
[name] => addressbook
)
[1] => mysql_xdevapi\Schema Object
(
[name] => information_schema
)
...
Session::getServerVersion
(No version information available, might only be in Git)
Session::getServerVersion — Get server version
Description
Retrieve the MySQL server version for the session.
Parameters
This function has no parameters.
Return Values
The MySQL server version for the session, as an integer such as "80012".
Examples
Example #1 mysql_xdevapi\Session::getServerVersion() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$version = $session->getServerVersion();
var_dump($version);
The above example will output something similar to:
int(80012)
Session::listClients
(No version information available, might only be in Git)
Session::listClients — Get client list
Description
Get a list of client connections to the session's MySQL server.
Parameters
This function has no parameters.
Return Values
An array containing the currently logged clients. The array elements are "client_id", "user", "host", and "sql_session".
Examples
Example #1 mysql_xdevapi\Session::listClients() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$ids = $session->listClients();
var_dump($ids);
?>
The above example will output something similar to:
array(1) {
[0]=>
array(4) {
["client_id"]=>
int(61)
["user"]=>
string(4) "root"
["host"]=>
string(9) "localhost"
["sql_session"]=>
int(72)
}
}
Session::quoteName
(No version information available, might only be in Git)
Session::quoteName — Add quotes
Description
$name
) : stringA quoting function to escape SQL names and identifiers. It escapes the identifier given in accordance to the settings of the current connection. This escape function should not be used to escape values.
Parameters
-
name -
The string to quote.
Return Values
The quoted string.
Examples
Example #1 mysql_xdevapi\Session::quoteName() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$first = "MySQL's test";
var_dump($first);
var_dump($session->quoteName($first));
$second = 'Another `test` "like" `this`';
var_dump($second);
var_dump($session->quoteName($second));
?>
The above example will output something similar to:
string(12) "MySQL's test" string(14) "`MySQL's test`" string(28) "Another `test` "like" `this`" string(34) "`Another ``test`` "like" ``this```"
Session::releaseSavepoint
(No version information available, might only be in Git)
Session::releaseSavepoint — Release set savepoint
Description
$name
) : voidRelease a previously set savepoint.
Parameters
-
name -
Name of the savepoint to release.
Return Values
An SqlStatementResult object.
Examples
Example #1 mysql_xdevapi\Session::releaseSavepoint() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$collection = $session->getSchema("addressbook")->getCollection("friends");
$session->startTransaction();
$collection->add( '{"test1":1, "test2":2}' )->execute();
$savepoint = $session->setSavepoint();
$collection->add( '{"test3":3, "test4":4}' )->execute();
$session->releaseSavepoint($savepoint);
$session->rollback();
?>
Session::rollback
(No version information available, might only be in Git)
Session::rollback — Rollback transaction
Description
Rollback the transaction.
Parameters
This function has no parameters.
Return Values
An SqlStatementResult object.
Examples
Example #1 mysql_xdevapi\Session::rollback() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$collection = $session->getSchema("addressbook")->getCollection("names");
$session->startTransaction();
$collection->add( '{"test1":1, "test2":2}' )->execute();
$savepoint = $session->setSavepoint();
$collection->add( '{"test3":3, "test4":4}' )->execute();
$session->releaseSavepoint($savepoint);
$session->rollback();
?>
Session::rollbackTo
(No version information available, might only be in Git)
Session::rollbackTo — Rollback transaction to savepoint
Description
$name
) : voidRollback the transaction back to the savepoint.
Parameters
-
name -
Name of the savepoint to rollback to; case-insensitive.
Return Values
An SqlStatementResult object.
Examples
Example #1 mysql_xdevapi\Session::rollbackTo() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$collection = $session->getSchema("addressbook")->getCollection("names");
$session->startTransaction();
$collection->add( '{"test1":1, "test2":2}' )->execute();
$savepoint1 = $session->setSavepoint();
$collection->add( '{"test3":3, "test4":4}' )->execute();
$savepoint2 = $session->setSavepoint();
$session->rollbackTo($savepoint1);
?>
Session::setSavepoint
(No version information available, might only be in Git)
Session::setSavepoint — Create savepoint
Description
$name
] ) : stringCreate a new savepoint for the transaction.
This function is currently not documented; only its argument list is available.
Parameters
-
name -
The name of the savepoint. The name is auto-generated if the optional
nameparameter is not defined as 'SAVEPOINT1', 'SAVEPOINT2', and so on.
Return Values
The name of the save point.
Examples
Example #1 mysql_xdevapi\Session::setSavepoint() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$collection = $session->getSchema("addressbook")->getCollection("names");
$session->startTransaction();
$collection->add( '{"test1":1, "test2":2}' )->execute();
$savepoint = $session->setSavepoint();
$collection->add( '{"test3":3, "test4":4}' )->execute();
$session->releaseSavepoint($savepoint);
$session->rollback();
?>
Session::sql
(No version information available, might only be in Git)
Session::sql — Execute SQL query
Description
Create a native SQL statement. Placeholders are supported using the native "?" syntax.
Use the execute method to execute the SQL statement.
Parameters
-
query -
SQL statement to execute.
Return Values
An SqlStatement object.
Examples
Example #1 mysql_xdevapi\Session::sql() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("CREATE DATABASE addressbook")->execute();
?>
Session::startTransaction
(No version information available, might only be in Git)
Session::startTransaction — Start transaction
Description
Start a new transaction.
Parameters
This function has no parameters.
Return Values
An SqlStatementResult object.
Examples
Example #1 mysql_xdevapi\Session::startTransaction() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$collection = $session->getSchema("addressbook")->getCollection("friends");
$session->startTransaction();
$collection->add( '{"test1":1, "test2":2}' )->execute();
$savepoint = $session->setSavepoint();
$collection->add( '{"test3":3, "test4":4}' )->execute();
$session->releaseSavepoint($savepoint);
$session->rollback();
?>
Table of Contents
- Session::close — Close session
- Session::commit — Commit transaction
- Session::__construct — Description constructor
- Session::createSchema — Create new schema
- Session::dropSchema — Drop a schema
- Session::generateUUID — Get new UUID
- Session::getDefaultSchema — Get default schema name
- Session::getSchema — Get a new schema object
- Session::getSchemas — Get the schemas
- Session::getServerVersion — Get server version
- Session::listClients — Get client list
- Session::quoteName — Add quotes
- Session::releaseSavepoint — Release set savepoint
- Session::rollback — Rollback transaction
- Session::rollbackTo — Rollback transaction to savepoint
- Session::setSavepoint — Create savepoint
- Session::sql — Execute SQL query
- Session::startTransaction — Start transaction
SqlStatement class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
Properties
- statement
Predefined Constants
mysql_xdevapi\SqlStatement::EXECUTE_ASYNCmysql_xdevapi\SqlStatement::BUFFERED
SqlStatement::bind
(No version information available, might only be in Git)
SqlStatement::bind — Bind statement parameters
Description
This function is currently not documented; only its argument list is available.
Parameters
-
param -
Return Values
Examples
Example #1 mysql_xdevapi\SqlStatement::bind() example
<?php
/* ... */
?>
SqlStatement::__construct
(No version information available, might only be in Git)
SqlStatement::__construct — Description constructor
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\SqlStatement::__construct() example
<?php
/* ... */
?>
SqlStatement::execute
(No version information available, might only be in Git)
SqlStatement::execute — Execute the operation
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\SqlStatement::execute() example
<?php
/* ... */
?>
SqlStatement::getNextResult
(No version information available, might only be in Git)
SqlStatement::getNextResult — Get next result
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\SqlStatement::getNextResult() example
<?php
/* ... */
?>
SqlStatement::getResult
(No version information available, might only be in Git)
SqlStatement::getResult — Get result
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\SqlStatement::getResult() example
<?php
/* ... */
?>
SqlStatement::hasMoreResults
(No version information available, might only be in Git)
SqlStatement::hasMoreResults — Check for more results
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
TRUE if the result set has more objects to fetch.
Examples
Example #1 mysql_xdevapi\SqlStatement::hasMoreResults() example
<?php
/* ... */
?>
Table of Contents
- SqlStatement::bind — Bind statement parameters
- SqlStatement::__construct — Description constructor
- SqlStatement::execute — Execute the operation
- SqlStatement::getNextResult — Get next result
- SqlStatement::getResult — Get result
- SqlStatement::hasMoreResults — Check for more results
SqlStatementResult class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
SqlStatementResult::__construct
(No version information available, might only be in Git)
SqlStatementResult::__construct — Description constructor
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\SqlStatementResult::__construct() example
<?php
/* ... */
?>
SqlStatementResult::fetchAll
(No version information available, might only be in Git)
SqlStatementResult::fetchAll — Get all rows from result
Description
Fetch all the rows from the result set.
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
A numerical array with all results from the query; each result is an associative array. An empty array is returned if no rows are present.
Examples
Example #1 mysql_xdevapi\SqlStatementResult::fetchAll() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS dbtest")->execute();
$session->sql("CREATE DATABASE dbtest")->execute();
$session->sql("CREATE TABLE dbtest.workers(name text, age int, job text)")->execute();
$session->sql("INSERT INTO dbtest.workers values ('John', 42, 'bricklayer'), ('Sam', 33, 'carpenter')")->execute();
$schema = $session->getSchema("dbtest");
$table = $schema->getTable("workers");
$rows = $session->sql("SELECT * FROM dbtest.workers")->execute()->fetchAll();
print_r($rows);
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[name] => John
[age] => 42
)
[1] => Array
(
[name] => Sam
[age] => 33
)
)
SqlStatementResult::fetchOne
(No version information available, might only be in Git)
SqlStatementResult::fetchOne — Get single row
Description
Fetch one row from the result set.
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
The result, as an associative array. In case there is not any result, null will be returned.
Examples
Example #1 mysql_xdevapi\SqlStatementResult::fetchOne() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS dbtest")->execute();
$session->sql("CREATE DATABASE dbtest")->execute();
$session->sql("CREATE TABLE dbtest.workers(name text, age int, job text)")->execute();
$session->sql("INSERT INTO dbtest.workers values ('John', 42, 'bricklayer'), ('Sam', 33, 'carpenter')")->execute();
$schema = $session->getSchema("dbtest");
$table = $schema->getTable("workers");
$rows = $session->sql("SELECT * FROM dbtest.workers")->execute()->fetchOne();
print_r($rows);
?>
The above example will output something similar to:
Array
(
[name] => John
[age] => 42
[job] => bricklayer
)
SqlStatementResult::getAffectedItemsCount
(No version information available, might only be in Git)
SqlStatementResult::getAffectedItemsCount — Get affected row count
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\SqlStatementResult::getAffectedItemsCount() example
<?php
/* ... */
?>
SqlStatementResult::getColumnsCount
(No version information available, might only be in Git)
SqlStatementResult::getColumnsCount — Get column count
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
The number of columns; 0 if there are none.
Changelog
| Version | Description |
|---|---|
| 8.0.14 | Method renamed from getColumnCount() to getColumnsCount(). |
Examples
Example #1 mysql_xdevapi\SqlStatementResult::getColumnsCount() example
<?php
/* ... */
?>
SqlStatementResult::getColumnNames
(No version information available, might only be in Git)
SqlStatementResult::getColumnNames — Get column names
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\SqlStatementResult::getColumnNames() example
<?php
/* ... */
?>
SqlStatementResult::getColumns
(No version information available, might only be in Git)
SqlStatementResult::getColumns — Get columns
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\SqlStatementResult::getColumns() example
<?php
/* ... */
?>
SqlStatementResult::getGeneratedIds
(No version information available, might only be in Git)
SqlStatementResult::getGeneratedIds — Get generated ids
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
An array of generated _id's from the last operation, or an empty array if there are none.
Examples
Example #1 mysql_xdevapi\SqlStatementResult::getGeneratedIds() example
<?php
/* ... */
?>
SqlStatementResult::getLastInsertId
(No version information available, might only be in Git)
SqlStatementResult::getLastInsertId — Get last insert id
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
The ID for the last insert operation.
Examples
Example #1 mysql_xdevapi\SqlStatementResult::getLastInsertId() example
<?php
/* ... */
?>
SqlStatementResult::getWarnings
(No version information available, might only be in Git)
SqlStatementResult::getWarnings — Get warnings from last operation
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
An array of Warning objects from the last operation. Each object defines an error 'message', error 'level', and error 'code'. An empty array is returned if no errors are present.
Examples
Example #1 mysql_xdevapi\SqlStatementResult::getWarnings() example
<?php
/* ... */
?>
SqlStatementResult::getWarningsCount
(No version information available, might only be in Git)
SqlStatementResult::getWarningsCount — Get warning count from last operation
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
The number of warnings raised during the last CRUD operation.
Examples
Example #1 mysql_xdevapi\SqlStatementResult::getWarningsCount() example
<?php
/* ... */
?>
SqlStatementResult::hasData
(No version information available, might only be in Git)
SqlStatementResult::hasData — Check if result has data
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
TRUE if the result set has data.
Examples
Example #1 mysql_xdevapi\SqlStatementResult::hasData() example
<?php
/* ... */
?>
SqlStatementResult::nextResult
(No version information available, might only be in Git)
SqlStatementResult::nextResult — Get next result
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
The next Result object from the result set.
Examples
Example #1 mysql_xdevapi\SqlStatementResult::nextResult() example
<?php
/* ... */
?>
Table of Contents
- SqlStatementResult::__construct — Description constructor
- SqlStatementResult::fetchAll — Get all rows from result
- SqlStatementResult::fetchOne — Get single row
- SqlStatementResult::getAffectedItemsCount — Get affected row count
- SqlStatementResult::getColumnsCount — Get column count
- SqlStatementResult::getColumnNames — Get column names
- SqlStatementResult::getColumns — Get columns
- SqlStatementResult::getGeneratedIds — Get generated ids
- SqlStatementResult::getLastInsertId — Get last insert id
- SqlStatementResult::getWarnings — Get warnings from last operation
- SqlStatementResult::getWarningsCount — Get warning count from last operation
- SqlStatementResult::hasData — Check if result has data
- SqlStatementResult::nextResult — Get next result
Statement class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
Predefined Constants
mysql_xdevapi\Statement::EXECUTE_ASYNCmysql_xdevapi\Statement::BUFFERED
Statement::__construct
(No version information available, might only be in Git)
Statement::__construct — Description constructor
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\Statement::__construct() example
<?php
/* ... */
?>
Statement::getNextResult
(No version information available, might only be in Git)
Statement::getNextResult — Get next result
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\Statement::getNextResult() example
<?php
/* ... */
?>
Statement::getResult
(No version information available, might only be in Git)
Statement::getResult — Get result
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\Statement::getResult() example
<?php
/* ... */
?>
Statement::hasMoreResults
(No version information available, might only be in Git)
Statement::hasMoreResults — Check if more results
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
Examples
Example #1 mysql_xdevapi\Statement::hasMoreResults() example
<?php
/* ... */
?>
Table of Contents
- Statement::__construct — Description constructor
- Statement::getNextResult — Get next result
- Statement::getResult — Get result
- Statement::hasMoreResults — Check if more results
Table class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Provides access to the table through INSERT/SELECT/UPDATE/DELETE statements.
Class synopsis
Properties
- name
Table::__construct
(No version information available, might only be in Git)
Table::__construct — Table constructor
Description
Construct a table object.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\Table::__construct() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
?>
Table::count
(No version information available, might only be in Git)
Table::count — Get row count
Description
Fetch the number of rows in the table.
Parameters
This function has no parameters.
Return Values
The total number of rows in the table.
Examples
Example #1 mysql_xdevapi\Table::count() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
var_dump($table->count());
?>
The above example will output:
int(2)
Table::delete
(No version information available, might only be in Git)
Table::delete — Delete rows from table
Description
Deletes rows from a table.
Parameters
This function has no parameters.
Return Values
A TableDelete object; use the execute() method to execute the delete query.
Examples
Example #1 mysql_xdevapi\Table::delete() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$table->delete()->where("name = :name")->orderby("age DESC")->limit(1)->bind(['name' => 'John'])->execute();
?>
Table::existsInDatabase
(No version information available, might only be in Git)
Table::existsInDatabase — Check if table exists in database
Description
Verifies if this table exists in the database.
Parameters
This function has no parameters.
Return Values
Returns TRUE if table exists in the database, else FALSE if it does not.
Examples
Example #1 mysql_xdevapi\Table::existsInDatabase() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
if ($table->existsInDatabase()) {
echo "Yes, this table still exists in the session's schema.";
}
?>
The above example will output something similar to:
Yes, this table still exists in the session's schema.
Table::getName
(No version information available, might only be in Git)
Table::getName — Get table name
Description
Returns the name of this database object.
Parameters
This function has no parameters.
Return Values
The name of this database object.
Examples
Example #1 mysql_xdevapi\Table::getName() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
var_dump($table->getName());
?>
The above example will output something similar to:
string(5) "names"
Table::getSchema
(No version information available, might only be in Git)
Table::getSchema — Get table schema
Description
Fetch the schema associated with the table.
Parameters
This function has no parameters.
Return Values
A Schema object.
Examples
Example #1 mysql_xdevapi\Table::getSchema() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
var_dump($table->getSchema());
?>
The above example will output something similar to:
object(mysql_xdevapi\Schema)#9 (1) {
["name"]=>
string(11) "addressbook"
}
Table::getSession
(No version information available, might only be in Git)
Table::getSession — Get table session
Description
Get session associated with the table.
Parameters
This function has no parameters.
Return Values
A Session object.
Examples
Example #1 mysql_xdevapi\Table::getSession() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
var_dump($table->getSession());
?>
The above example will output something similar to:
object(mysql_xdevapi\Session)#9 (0) {
}
Table::insert
(No version information available, might only be in Git)
Table::insert — Insert table rows
Description
Inserts rows into a table.
Parameters
-
columns -
The columns to insert data into. Can be an array with one or more values, or a string.
-
... -
Additional columns definitions.
Return Values
A TableInsert object; use the execute() method to execute the insert statement.
Examples
Example #1 mysql_xdevapi\Table::insert() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$table ->insert("name", "age")
->values(["Suzanne", 31],["Julie", 43])
->execute();
?>
Table::isView
(No version information available, might only be in Git)
Table::isView — Check if table is view
Description
Determine if the underlying object is a view or not.
Parameters
This function has no parameters.
Return Values
TRUE if the underlying object is a view, otherwise FALSE.
Examples
Example #1 mysql_xdevapi\Table::isView() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names
if ($table->isView()) {
echo "This is a view.";
} else {
echo "This is not a view.";
}
?>
The above example will output:
int(2)
Table::select
(No version information available, might only be in Git)
Table::select — Select rows from table
Description
Fetches data from a table.
Parameters
-
columns -
The columns to select data from. Can be an array with one or more values, or a string.
-
... -
Additional columns parameter definitions.
Return Values
A TableSelect object; use the execute() method to execute the select and return a RowResult object.
Examples
Example #1 mysql_xdevapi\Table::count() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$row = $table->select('name', 'age')->execute()->fetchAll();
print_r($row);
The above example will output something similar to:
Array
(
[0] => Array
(
[name] => John
[age] => 42
)
[1] => Array
(
[name] => Sam
[age] => 33
)
)
Table::update
(No version information available, might only be in Git)
Table::update — Update rows in table
Description
Updates columns in a table.
Parameters
This function has no parameters.
Return Values
A TableUpdate object; use the execute() method to execute the update statement.
Examples
Example #1 mysql_xdevapi\Table::update() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$table->update()->set('age',34)->where('name = "Sam"')->limit(1)->execute();
?>
Table of Contents
- Table::__construct — Table constructor
- Table::count — Get row count
- Table::delete — Delete rows from table
- Table::existsInDatabase — Check if table exists in database
- Table::getName — Get table name
- Table::getSchema — Get table schema
- Table::getSession — Get table session
- Table::insert — Insert table rows
- Table::isView — Check if table is view
- Table::select — Select rows from table
- Table::update — Update rows in table
TableDelete class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
A statement for delete operations on Table.
Class synopsis
TableDelete::bind
(No version information available, might only be in Git)
TableDelete::bind — Bind delete query parameters
Description
Binds a value to a specific placeholder.
Parameters
-
placeholder_values -
The name of the placeholder and the value to bind.
Return Values
A TableDelete object.
Examples
Example #1 mysql_xdevapi\TableDelete::bind() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$table->delete()
->where("name = :name")
->bind(['name' => 'John'])
->orderby("age DESC")
->limit(1)
->execute();
?>
TableDelete::__construct
(No version information available, might only be in Git)
TableDelete::__construct — TableDelete constructor
Description
Initiated by using the delete() method.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\TableDelete::__construct() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$table->delete()
->where("name = :name")
->bind(['name' => 'John'])
->orderby("age DESC")
->limit(1)
->execute();
?>
TableDelete::execute
(No version information available, might only be in Git)
TableDelete::execute — Execute delete query
Description
Execute the delete query.
Parameters
This function has no parameters.
Return Values
A Result object.
Examples
Example #1 mysql_xdevapi\TableDelete::execute() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$table->delete()
->where("name = :name")
->bind(['name' => 'John'])
->orderby("age DESC")
->limit(1)
->execute();
?>
TableDelete::limit
(No version information available, might only be in Git)
TableDelete::limit — Limit deleted rows
Description
Sets the maximum number of records or documents to delete.
Parameters
-
rows -
The maximum number of records or documents to delete.
Return Values
TableDelete object.
Examples
Example #1 mysql_xdevapi\TableDelete::limit() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$table->delete()
->where("name = :name")
->bind(['name' => 'John'])
->orderby("age DESC")
->limit(1)
->execute();
?>
TableDelete::orderby
(No version information available, might only be in Git)
TableDelete::orderby — Set delete sort criteria
Description
Set the order options for a result set.
Parameters
-
orderby_expr -
The sort definition.
Return Values
A TableDelete object.
Examples
Example #1 mysql_xdevapi\TableDelete::orderBy() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$table->delete()
->where("age = :age")
->bind(['age' => 42])
->orderby("name DESC")
->limit(1)
->execute();
?>
TableDelete::where
(No version information available, might only be in Git)
TableDelete::where — Set delete search condition
Description
Sets the search condition to filter.
Parameters
-
where_expr -
Define the search condition to filter documents or records.
Return Values
TableDelete object.
Examples
Example #1 mysql_xdevapi\TableDelete::where() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$table->delete()
->where("id = :id")
->bind(['id' => 42])
->limit(1)
->execute();
?>
Table of Contents
- TableDelete::bind — Bind delete query parameters
- TableDelete::__construct — TableDelete constructor
- TableDelete::execute — Execute delete query
- TableDelete::limit — Limit deleted rows
- TableDelete::orderby — Set delete sort criteria
- TableDelete::where — Set delete search condition
TableInsert class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
A statement for insert operations on Table.
Class synopsis
TableInsert::__construct
(No version information available, might only be in Git)
TableInsert::__construct — TableInsert constructor
Description
Initiated by using the insert() method.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\TableInsert::__construct() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$table
->insert("name", "age")
->values(["Suzanne", 31],["Julie", 43])
->execute();
?>
TableInsert::execute
(No version information available, might only be in Git)
TableInsert::execute — Execute insert query
Description
Execute the statement.
Parameters
This function has no parameters.
Return Values
A Result object.
Examples
Example #1 mysql_xdevapi\TableInsert::execute() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$table
->insert("name", "age")
->values(["Suzanne", 31],["Julie", 43])
->execute();
?>
TableInsert::values
(No version information available, might only be in Git)
TableInsert::values — Add insert row values
Description
Set the values to be inserted.
Parameters
-
row_values -
Values (an array) of columns to insert.
Return Values
A TableInsert object.
Examples
Example #1 mysql_xdevapi\TableInsert::values() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$table
->insert("name", "age")
->values(["Suzanne", 31],["Julie", 43])
->execute();
?>
Table of Contents
- TableInsert::__construct — TableInsert constructor
- TableInsert::execute — Execute insert query
- TableInsert::values — Add insert row values
TableSelect class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
A statement for record retrieval operations on a Table.
Class synopsis
TableSelect::bind
(No version information available, might only be in Git)
TableSelect::bind — Bind select query parameters
Description
Binds a value to a specific placeholder.
Parameters
-
placeholder_values -
The name of the placeholder, and the value to bind.
Return Values
A TableSelect object.
Examples
Example #1 mysql_xdevapi\TableSelect::bind() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$result = $table->select('name','age')
->where('name like :name and age > :age')
->bind(['name' => 'John', 'age' => 42])
->execute();
$row = $result->fetchAll();
print_r($row);
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[name] => John
[age] => 42
)
)
TableSelect::__construct
(No version information available, might only be in Git)
TableSelect::__construct — TableSelect constructor
Description
An object returned by the select() method; use execute() to execute the query.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\TableSelect::__construct() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 33)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$result = $table->select('name','age')
->where('name like :name and age > :age')
->bind(['name' => 'John', 'age' => 42])
->orderBy('age desc')
->execute();
$row = $result->fetchAll();
print_r($row);
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[name] => John
[age] => 42
)
)
TableSelect::execute
(No version information available, might only be in Git)
TableSelect::execute — Execute select statement
Description
Execute the select statement by chaining it with the execute() method.
Parameters
This function has no parameters.
Return Values
A RowResult object.
Examples
Example #1 mysql_xdevapi\TableSelect::execute() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$result = $table->select('name','age')
->where('name like :name and age > :age')
->bind(['name' => 'John', 'age' => 42])
->orderBy('age desc')
->execute();
$row = $result->fetchAll();
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[name] => John
[age] => 42
)
)
TableSelect::groupBy
(No version information available, might only be in Git)
TableSelect::groupBy — Set select grouping criteria
Description
Sets a grouping criteria for the result set.
Parameters
-
sort_expr -
The grouping criteria.
Return Values
A TableSelect object.
Examples
Example #1 mysql_xdevapi\TableSelect::groupBy() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 42)")->execute();
$session->sql("INSERT INTO addressbook.names values ('Suki', 31)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$result = $table->select('count(*) as count', 'age')
->groupBy('age')->orderBy('age asc')
->execute();
$row = $result->fetchAll();
print_r($row);
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[count] => 1
[age] => 31
)
[1] => Array
(
[count] => 2
[age] => 42
)
)
TableSelect::having
(No version information available, might only be in Git)
TableSelect::having — Set select having condition
Description
Sets a condition for records to consider in aggregate function operations.
Parameters
-
sort_expr -
A condition on the aggregate functions used on the grouping criteria.
Return Values
A TableSelect object.
Examples
Example #1 mysql_xdevapi\TableSelect::having() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 42)")->execute();
$session->sql("INSERT INTO addressbook.names values ('Suki', 31)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$result = $table->select('count(*) as count', 'age')
->groupBy('age')->orderBy('age asc')
->having('count > 1')
->execute();
$row = $result->fetchAll();
print_r($row);
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[count] => 2
[age] => 42
)
)
TableSelect::limit
(No version information available, might only be in Git)
TableSelect::limit — Limit selected rows
Description
Sets the maximum number of records or documents to return.
Parameters
-
rows -
The maximum number of records or documents.
Return Values
A TableSelect object.
Examples
Example #1 mysql_xdevapi\TableSelect::limit() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$result = $table->select('name', 'age')
->limit(1)
->execute();
$row = $result->fetchAll();
print_r($row);
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[name] => John
[age] => 42
)
)
TableSelect::lockExclusive
(No version information available, might only be in Git)
TableSelect::lockExclusive — Execute EXCLUSIVE LOCK
Description
$lock_waiting_option
] ) : mysql_xdevapi\TableSelectExecute a read operation with EXCLUSIVE LOCK. Only one lock can be active at a time.
Parameters
-
lock_waiting_option -
The optional waiting option that defaults to
MYSQLX_LOCK_DEFAULT. Valid values are:MYSQLX_LOCK_DEFAULTMYSQLX_LOCK_NOWAITMYSQLX_LOCK_SKIP_LOCKED
Return Values
TableSelect object.
Examples
Example #1 mysql_xdevapi\TableSelect::lockExclusive() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$session->startTransaction();
$result = $table->select('name', 'age')
->lockExclusive(MYSQLX_LOCK_NOWAIT)
->execute();
$session->commit();
$row = $result->fetchAll();
print_r($row);
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[name] => John
[age] => 42
)
[1] => Array
(
[name] => Sam
[age] => 42
)
)
TableSelect::offset
(No version information available, might only be in Git)
TableSelect::offset — Set limit offset
Description
Skip given number of rows in result.
Parameters
-
position -
The limit offset.
Return Values
A TableSelect object.
Examples
Example #1 mysql_xdevapi\TableSelect::offset() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$session->sql("DROP DATABASE IF EXISTS addressbook")->execute();
$session->sql("CREATE DATABASE addressbook")->execute();
$session->sql("CREATE TABLE addressbook.names(name text, age int)")->execute();
$session->sql("INSERT INTO addressbook.names values ('John', 42), ('Sam', 42)")->execute();
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$result = $table->select('name', 'age')
->limit(1)
->offset(1)
->execute();
$row = $result->fetchAll();
print_r($row);
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[name] => Sam
[age] => 42
)
)
TableSelect::orderby
(No version information available, might only be in Git)
TableSelect::orderby — Set select sort criteria
Description
$sort_expr
[, mixed $...
] ) : mysql_xdevapi\TableSelectSets the order by criteria.
Parameters
-
sort_expr -
The expressions that define the order by criteria. Can be an array with one or more expressions, or a string.
-
... -
Additional sort_expr parameters.
Return Values
A TableSelect object.
Examples
Example #1 mysql_xdevapi\TableSelect::orderBy() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$result = $table->select('name', 'age')
->orderBy('name desc')
->execute();
$row = $result->fetchAll();
print_r($row);
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[name] => Sam
[age] => 42
)
[1] => Array
(
[name] => John
[age] => 42
)
)
TableSelect::where
(No version information available, might only be in Git)
TableSelect::where — Set select search condition
Description
Sets the search condition to filter.
Parameters
-
where_expr -
Define the search condition to filter documents or records.
Return Values
A TableSelect object.
Examples
Example #1 mysql_xdevapi\TableSelect::where() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$result = $table->select('name','age')
->where('name like :name and age > :age')
->bind(['name' => 'John', 'age' => 42])
->execute();
$row = $result->fetchAll();
print_r($row);
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[name] => John
[age] => 42
)
)
Table of Contents
- TableSelect::bind — Bind select query parameters
- TableSelect::__construct — TableSelect constructor
- TableSelect::execute — Execute select statement
- TableSelect::groupBy — Set select grouping criteria
- TableSelect::having — Set select having condition
- TableSelect::limit — Limit selected rows
- TableSelect::lockExclusive — Execute EXCLUSIVE LOCK
- TableSelect::lockShared — Execute SHARED LOCK
- TableSelect::offset — Set limit offset
- TableSelect::orderby — Set select sort criteria
- TableSelect::where — Set select search condition
TableUpdate class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
A statement for record update operations on a Table.
Class synopsis
TableUpdate::bind
(No version information available, might only be in Git)
TableUpdate::bind — Bind update query parameters
Description
Binds a value to a specific placeholder.
Parameters
-
placeholder_values -
The name of the placeholder, and the value to bind, defined as a JSON array.
Return Values
A TableUpdate object.
Examples
Example #1 mysql_xdevapi\TableUpdate::bind() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$table->update()
->set('status', 'admin')
->where('name = :name and age > :age')
->bind(['name' => 'Bernie', 'age' => 2000])
->execute();
?>
TableUpdate::__construct
(No version information available, might only be in Git)
TableUpdate::__construct — TableUpdate constructor
Description
Initiated by using the update() method.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\TableUpdate::__construct() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$res = $table->update()
->set('level', 3)
->where('age > 15 and age < 22')
->limit(4)
->orderby(['age asc','name desc'])
->execute();
?>
TableUpdate::execute
(No version information available, might only be in Git)
TableUpdate::execute — Execute update query
Description
Executes the update statement.
Parameters
This function has no parameters.
Return Values
A TableUpdate object.
Examples
Example #1 mysql_xdevapi\TableUpdate::execute() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$res = $table->update()
->set('level', 3)
->where('age > 15 and age < 22')
->limit(4)
->orderby(['age asc','name desc'])
->execute();
?>
TableUpdate::limit
(No version information available, might only be in Git)
TableUpdate::limit — Limit update row count
Description
Set the maximum number of records or documents update.
Parameters
-
rows -
The maximum number of records or documents to update.
Return Values
A TableUpdate object.
Examples
Example #1 mysql_xdevapi\TableUpdate::limit() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$res = $table->update()
->set('level', 3)
->where('age > 15 and age < 22')
->limit(4)
->orderby(['age asc','name desc'])
->execute();
?>
TableUpdate::orderby
(No version information available, might only be in Git)
TableUpdate::orderby — Set sorting criteria
Description
$orderby_expr
[, mixed $...
] ) : mysql_xdevapi\TableUpdateSets the sorting criteria.
Parameters
-
orderby_expr -
The expressions that define the order by criteria. Can be an array with one or more expressions, or a string.
-
... -
Additional sort_expr parameters.
Return Values
TableUpdate object.
Examples
Example #1 mysql_xdevapi\TableUpdate::orderby() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$res = $table->update()
->set('level', 3)
->where('age > 15 and age < 22')
->limit(4)
->orderby(['age asc','name desc'])
->execute();
?>
TableUpdate::set
(No version information available, might only be in Git)
TableUpdate::set — Add field to be updated
Description
$table_field
, string $expression_or_literal
) : mysql_xdevapi\TableUpdateUpdates the column value on records in a table.
Parameters
-
table_field -
The column name to be updated.
-
expression_or_literal -
The value to be set on the specified column.
Return Values
TableUpdate object.
Examples
Example #1 mysql_xdevapi\TableUpdate::set() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$res = $table->update()
->set('level', 3)
->where('age > 15 and age < 22')
->limit(4)
->orderby(['age asc','name desc'])
->execute();
?>
TableUpdate::where
(No version information available, might only be in Git)
TableUpdate::where — Set search filter
Description
Set the search condition to filter.
Parameters
-
where_expr -
The search condition to filter documents or records.
Return Values
A TableUpdate object.
Examples
Example #1 mysql_xdevapi\TableUpdate::where() example
<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$schema = $session->getSchema("addressbook");
$table = $schema->getTable("names");
$res = $table->update()
->set('level', 3)
->where('age > 15 and age < 22')
->limit(4)
->orderby(['age asc','name desc'])
->execute();
?>
Table of Contents
- TableUpdate::bind — Bind update query parameters
- TableUpdate::__construct — TableUpdate constructor
- TableUpdate::execute — Execute update query
- TableUpdate::limit — Limit update row count
- TableUpdate::orderby — Set sorting criteria
- TableUpdate::set — Add field to be updated
- TableUpdate::where — Set search filter
Warning class
(PECL mysql-xdevapi >= 8.0.11)
Introduction
Class synopsis
Properties
- message
- level
- code
Warning::__construct
(No version information available, might only be in Git)
Warning::__construct — Warning constructor
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Examples
Example #1 mysql_xdevapi\Warning::__construct() example
<?php
/* ... */
?>
Table of Contents
- Warning::__construct — Warning constructor
- Introduction
- Installing/Configuring
- Predefined Constants
- Examples
- Mysql_xdevapi Functions
- expression — Bind prepared statement variables as parameters
- getSession — Connect to a MySQL server
- mysql_xdevapi\BaseResult — BaseResult interface
- BaseResult::getWarnings — Fetch warnings from last operation
- BaseResult::getWarningsCount — Fetch warning count from last operation
- mysql_xdevapi\Client — Client class
- mysql_xdevapi\Client::close — Close client
- Client::__construct — Client constructor
- Client::getClient — Get client session
- mysql_xdevapi\Collection — Collection class
- Collection::add — Add collection document
- Collection::addOrReplaceOne — Add or replace collection document
- Collection::__construct — Collection constructor
- Collection::count — Get document count
- Collection::createIndex — Create collection index
- Collection::dropIndex — Drop collection index
- Collection::existsInDatabase — Check if collection exists in database
- Collection::find — Search for document
- Collection::getName — Get collection name
- Collection::getOne — Get one document
- Collection::getSchema — Get schema object
- Collection::getSession — Get session object
- Collection::modify — Modify collection documents
- Collection::remove — Remove collection documents
- Collection::removeOne — Remove one collection document
- Collection::replaceOne — Replace one collection document
- mysql_xdevapi\CollectionAdd — CollectionAdd class
- CollectionAdd::__construct — CollectionAdd constructor
- CollectionAdd::execute — Execute the statement
- mysql_xdevapi\CollectionFind — CollectionFind class
- CollectionFind::bind — Bind value to query placeholder
- CollectionFind::__construct — CollectionFind constructor
- CollectionFind::execute — Execute the statement
- CollectionFind::fields — Set document field filter
- CollectionFind::groupBy — Set grouping criteria
- CollectionFind::having — Set condition for aggregate functions
- CollectionFind::limit — Limit number of returned documents
- CollectionFind::lockExclusive — Execute operation with EXCLUSIVE LOCK
- CollectionFind::lockShared — Execute operation with SHARED LOCK
- CollectionFind::offset — Skip given number of elements to be returned
- CollectionFind::sort — Set the sorting criteria
- mysql_xdevapi\CollectionModify — CollectionModify class
- CollectionModify::arrayAppend — Append element to an array field
- CollectionModify::arrayInsert — Insert element into an array field
- CollectionModify::bind — Bind value to query placeholder
- CollectionModify::__construct — CollectionModify constructor
- CollectionModify::execute — Execute modify operation
- CollectionModify::limit — Limit number of modified documents
- CollectionModify::patch — Patch document
- CollectionModify::replace — Replace document field
- CollectionModify::set — Set document attribute
- CollectionModify::skip — Skip elements
- CollectionModify::sort — Set the sorting criteria
- CollectionModify::unset — Unset the value of document fields
- mysql_xdevapi\CollectionRemove — CollectionRemove class
- CollectionRemove::bind — Bind value to placeholder
- CollectionRemove::__construct — CollectionRemove constructor
- CollectionRemove::execute — Execute remove operation
- CollectionRemove::limit — Limit number of documents to remove
- CollectionRemove::sort — Set the sorting criteria
- mysql_xdevapi\ColumnResult — ColumnResult class
- ColumnResult::__construct — ColumnResult constructor
- ColumnResult::getCharacterSetName — Get character set
- ColumnResult::getCollationName — Get collation name
- ColumnResult::getColumnLabel — Get column label
- ColumnResult::getColumnName — Get column name
- ColumnResult::getFractionalDigits — Get fractional digit length
- ColumnResult::getLength — Get column field length
- ColumnResult::getSchemaName — Get schema name
- ColumnResult::getTableLabel — Get table label
- ColumnResult::getTableName — Get table name
- ColumnResult::getType — Get column type
- ColumnResult::isNumberSigned — Check if signed type
- ColumnResult::isPadded — Check if padded
- mysql_xdevapi\CrudOperationBindable — CrudOperationBindable interface
- CrudOperationBindable::bind — Bind value to placeholder
- mysql_xdevapi\CrudOperationLimitable — CrudOperationLimitable interface
- CrudOperationLimitable::limit — Set result limit
- mysql_xdevapi\CrudOperationSkippable — CrudOperationSkippable interface
- CrudOperationSkippable::skip — Number of operations to skip
- mysql_xdevapi\CrudOperationSortable — CrudOperationSortable interface
- CrudOperationSortable::sort — Sort results
- mysql_xdevapi\DatabaseObject — DatabaseObject interface
- DatabaseObject::existsInDatabase — Check if object exists in database
- DatabaseObject::getName — Get object name
- DatabaseObject::getSession — Get session name
- mysql_xdevapi\DocResult — DocResult class
- DocResult::__construct — DocResult constructor
- DocResult::fetchAll — Get all rows
- DocResult::fetchOne — Get one row
- DocResult::getWarnings — Get warnings from last operation
- DocResult::getWarningsCount — Get warning count from last operation
- mysql_xdevapi\Exception — Exception class
- mysql_xdevapi\Executable — Executable interface
- Executable::execute — Execute statement
- mysql_xdevapi\ExecutionStatus — ExecutionStatus class
- ExecutionStatus::__construct — ExecutionStatus constructor
- mysql_xdevapi\Expression — Expression class
- Expression::__construct — Expression constructor
- mysql_xdevapi\Result — Result class
- Result::__construct — Result constructor
- Result::getAffectedItemsCount — Get affected row count
- Result::getAutoIncrementValue — Get autoincremented value
- Result::getGeneratedIds — Get generated ids
- Result::getWarnings — Get warnings from last operation
- Result::getWarningsCount — Get warning count from last operation
- mysql_xdevapi\RowResult — RowResult class
- RowResult::__construct — RowResult constructor
- RowResult::fetchAll — Get all rows from result
- RowResult::fetchOne — Get row from result
- RowResult::getColumnsCount — Get column count
- RowResult::getColumnNames — Get all column names
- RowResult::getColumns — Get column metadata
- RowResult::getWarnings — Get warnings from last operation
- RowResult::getWarningsCount — Get warning count from last operation
- mysql_xdevapi\Schema — Schema class
- Schema::__construct — constructor
- Schema::createCollection — Add collection to schema
- Schema::dropCollection — Drop collection from schema
- Schema::existsInDatabase — Check if exists in database
- Schema::getCollection — Get collection from schema
- Schema::getCollectionAsTable — Get collection table object
- Schema::getCollections — Get all schema collections
- Schema::getName — Get schema name
- Schema::getSession — Get schema session
- Schema::getTable — Get schema table
- Schema::getTables — Get schema tables
- mysql_xdevapi\SchemaObject — SchemaObject interface
- SchemaObject::getSchema — Get schema object
- mysql_xdevapi\Session — Session class
- Session::close — Close session
- Session::commit — Commit transaction
- Session::__construct — Description constructor
- Session::createSchema — Create new schema
- Session::dropSchema — Drop a schema
- Session::generateUUID — Get new UUID
- Session::getDefaultSchema — Get default schema name
- Session::getSchema — Get a new schema object
- Session::getSchemas — Get the schemas
- Session::getServerVersion — Get server version
- Session::listClients — Get client list
- Session::quoteName — Add quotes
- Session::releaseSavepoint — Release set savepoint
- Session::rollback — Rollback transaction
- Session::rollbackTo — Rollback transaction to savepoint
- Session::setSavepoint — Create savepoint
- Session::sql — Execute SQL query
- Session::startTransaction — Start transaction
- mysql_xdevapi\SqlStatement — SqlStatement class
- SqlStatement::bind — Bind statement parameters
- SqlStatement::__construct — Description constructor
- SqlStatement::execute — Execute the operation
- SqlStatement::getNextResult — Get next result
- SqlStatement::getResult — Get result
- SqlStatement::hasMoreResults — Check for more results
- mysql_xdevapi\SqlStatementResult — SqlStatementResult class
- SqlStatementResult::__construct — Description constructor
- SqlStatementResult::fetchAll — Get all rows from result
- SqlStatementResult::fetchOne — Get single row
- SqlStatementResult::getAffectedItemsCount — Get affected row count
- SqlStatementResult::getColumnsCount — Get column count
- SqlStatementResult::getColumnNames — Get column names
- SqlStatementResult::getColumns — Get columns
- SqlStatementResult::getGeneratedIds — Get generated ids
- SqlStatementResult::getLastInsertId — Get last insert id
- SqlStatementResult::getWarnings — Get warnings from last operation
- SqlStatementResult::getWarningsCount — Get warning count from last operation
- SqlStatementResult::hasData — Check if result has data
- SqlStatementResult::nextResult — Get next result
- mysql_xdevapi\Statement — Statement class
- Statement::__construct — Description constructor
- Statement::getNextResult — Get next result
- Statement::getResult — Get result
- Statement::hasMoreResults — Check if more results
- mysql_xdevapi\Table — Table class
- Table::__construct — Table constructor
- Table::count — Get row count
- Table::delete — Delete rows from table
- Table::existsInDatabase — Check if table exists in database
- Table::getName — Get table name
- Table::getSchema — Get table schema
- Table::getSession — Get table session
- Table::insert — Insert table rows
- Table::isView — Check if table is view
- Table::select — Select rows from table
- Table::update — Update rows in table
- mysql_xdevapi\TableDelete — TableDelete class
- TableDelete::bind — Bind delete query parameters
- TableDelete::__construct — TableDelete constructor
- TableDelete::execute — Execute delete query
- TableDelete::limit — Limit deleted rows
- TableDelete::orderby — Set delete sort criteria
- TableDelete::where — Set delete search condition
- mysql_xdevapi\TableInsert — TableInsert class
- TableInsert::__construct — TableInsert constructor
- TableInsert::execute — Execute insert query
- TableInsert::values — Add insert row values
- mysql_xdevapi\TableSelect — TableSelect class
- TableSelect::bind — Bind select query parameters
- TableSelect::__construct — TableSelect constructor
- TableSelect::execute — Execute select statement
- TableSelect::groupBy — Set select grouping criteria
- TableSelect::having — Set select having condition
- TableSelect::limit — Limit selected rows
- TableSelect::lockExclusive — Execute EXCLUSIVE LOCK
- TableSelect::lockShared — Execute SHARED LOCK
- TableSelect::offset — Set limit offset
- TableSelect::orderby — Set select sort criteria
- TableSelect::where — Set select search condition
- mysql_xdevapi\TableUpdate — TableUpdate class
- TableUpdate::bind — Bind update query parameters
- TableUpdate::__construct — TableUpdate constructor
- TableUpdate::execute — Execute update query
- TableUpdate::limit — Limit update row count
- TableUpdate::orderby — Set sorting criteria
- TableUpdate::set — Add field to be updated
- TableUpdate::where — Set search filter
- mysql_xdevapi\Warning — Warning class
- Warning::__construct — Warning constructor
Original MySQL API
Introduction
This extension is deprecated as of PHP 5.5.0, and has been removed as of PHP 7.0.0. Instead, either the mysqli or PDO_MySQL extension should be used. See also the MySQL API Overview for further help while choosing a MySQL API.
These functions allow you to access MySQL database servers. More information about MySQL can be found at » http://www.mysql.com/.
Documentation for MySQL can be found at » http://dev.mysql.com/doc/.
Installing/Configuring
Table of Contents
Requirements
In order to have these functions available, you must compile PHP with MySQL support.
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Installation
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
For compiling, simply use the
--with-mysql[=DIR]
configuration option where the optional [DIR] points to
the MySQL installation directory.
Although this MySQL extension is compatible with MySQL 4.1.0 and greater, it doesn't support the extra functionality that these versions provide. For that, use the MySQLi extension.
If you would like to install the mysql extension along with the mysqli extension you have to use the same client library to avoid any conflicts.
Installation on Linux Systems
Note: [DIR] is the path to the MySQL client library
files (headers and libraries), which can be downloaded from
» MySQL.
| PHP Version | Default | Configure Options: mysqlnd | Configure Options: libmysqlclient |
Changelog |
|---|---|---|---|---|
| 4.x.x | libmysqlclient | Not Available | --without-mysql to disable | MySQL enabled by default, MySQL client libraries are bundled |
| 5.0.x, 5.1.x, 5.2.x | libmysqlclient | Not Available | --with-mysql=[DIR] | MySQL is no longer enabled by default, and the MySQL client libraries are no longer bundled |
| 5.3.x | libmysqlclient | --with-mysql=mysqlnd | --with-mysql=[DIR] | mysqlnd is now available |
| 5.4.x | mysqlnd | --with-mysql | --with-mysql=[DIR] | mysqlnd is now the default |
Installation on Windows Systems
PHP 5.0.x, 5.1.x, 5.2.x
MySQL is no longer enabled by default, so the php_mysql.dll DLL must be enabled inside of php.ini. Also, PHP needs access to the MySQL client library. A file named libmysql.dll is included in the Windows PHP distribution and in order for PHP to talk to MySQL this file needs to be available to the Windows systems PATH. See the FAQ titled "How do I add my PHP directory to the PATH on Windows" for information on how to do this. Although copying libmysql.dll to the Windows system directory also works (because the system directory is by default in the system's PATH), it's not recommended.
As with enabling any PHP extension (such as
php_mysql.dll), the PHP directive
extension_dir should be set to
the directory where the PHP extensions are located. See also the
Manual Windows Installation
Instructions. An example extension_dir value for PHP 5 is
c:\php\ext
Note:
If when starting the web server an error similar to the following occurs:
"Unable to load dynamic library './php_mysql.dll'", this is because php_mysql.dll and/or libmysql.dll cannot be found by the system.
PHP 5.3.0+
The MySQL Native Driver is enabled by default. Include php_mysql.dll, but libmysql.dll is no longer required or used.
MySQL Installation Notes
Crashes and startup problems of PHP may be encountered when loading this extension in conjunction with the recode extension. See the recode extension for more information.
Note:
If you need charsets other than latin (default), you have to install external (not bundled) libmysqlclient with compiled charset support.
Runtime Configuration
The behaviour of these functions is affected by settings in php.ini.
| Name | Default | Changeable | Changelog |
|---|---|---|---|
| mysql.allow_local_infile | "1" | PHP_INI_SYSTEM | |
| mysql.allow_persistent | "1" | PHP_INI_SYSTEM | |
| mysql.max_persistent | "-1" | PHP_INI_SYSTEM | |
| mysql.max_links | "-1" | PHP_INI_SYSTEM | |
| mysql.trace_mode | "0" | PHP_INI_ALL | |
| mysql.default_port | NULL | PHP_INI_ALL | |
| mysql.default_socket | NULL | PHP_INI_ALL | |
| mysql.default_host | NULL | PHP_INI_ALL | |
| mysql.default_user | NULL | PHP_INI_ALL | |
| mysql.default_password | NULL | PHP_INI_ALL | |
| mysql.connect_timeout | "60" | PHP_INI_ALL |
Here's a short explanation of the configuration directives.
-
mysql.allow_local_infileinteger -
Allow accessing, from PHP's perspective, local files with LOAD DATA statements
-
mysql.allow_persistentboolean -
Whether to allow persistent connections to MySQL.
-
mysql.max_persistentinteger -
The maximum number of persistent MySQL connections per process.
-
mysql.max_linksinteger -
The maximum number of MySQL connections per process, including persistent connections.
-
mysql.trace_modeboolean -
Trace mode. When
mysql.trace_modeis enabled, warnings for table/index scans, non free result sets, and SQL-Errors will be displayed. (Introduced in PHP 4.3.0) -
mysql.default_portstring -
The default TCP port number to use when connecting to the database server if no other port is specified. If no default is specified, the port will be obtained from the MYSQL_TCP_PORT environment variable, the
mysql-tcpentry in /etc/services or the compile-timeMYSQL_PORTconstant, in that order. Win32 will only use theMYSQL_PORTconstant. -
mysql.default_socketstring -
The default socket name to use when connecting to a local database server if no other socket name is specified.
-
mysql.default_hoststring -
The default server host to use when connecting to the database server if no other host is specified. Doesn't apply in SQL safe mode.
-
mysql.default_userstring -
The default user name to use when connecting to the database server if no other name is specified. Doesn't apply in SQL safe mode.
-
mysql.default_passwordstring -
The default password to use when connecting to the database server if no other password is specified. Doesn't apply in SQL safe mode.
-
mysql.connect_timeoutinteger -
Connect timeout in seconds. On Linux this timeout is also used for waiting for the first answer from the server.
Resource Types
There are two resource types used in the MySQL module. The first one is the link identifier for a database connection, the second a resource which holds the result of a query.
Changelog
The following changes have been made to classes/functions/methods of this extension.
General Changelog for the ext/mysql extension
This changelog references the ext/mysql extension.
Global ext/mysql changes
The following is a list of changes to the entire ext/mysql extension.
| Version | Description |
|---|---|
| 7.0.0 |
This extension was removed from PHP. For details, see Choosing an API. |
| 5.5.0 |
This extension has been deprecated. Connecting to a MySQL database
via mysql_connect(),
mysql_pconnect() or an implicit connection via any
other |
| 5.5.0 |
All of the old deprecated functions and aliases now emit
mysql(), mysql_fieldname(), mysql_fieldtable(), mysql_fieldlen(), mysql_fieldtype(), mysql_fieldflags(), mysql_selectdb(), mysql_createdb(), mysql_dropdb(), mysql_freeresult(), mysql_numfields(), mysql_numrows(), mysql_listdbs(), mysql_listtables(), mysql_listfields(), mysql_db_name(), mysql_dbname(), mysql_tablename(), and mysql_table_name(). |
Changes to existing functions
The following list is a compilation of changelog entries from the ext/mysql functions.
| Version | Function | Description |
|---|---|---|
| 5.5.0 | mysql_connect | This function will generate an E_DEPRECATED error. |
| mysql_db_name | The mysql_list_dbs function is deprecated, and emits an E_DEPRECATED level error. | |
| mysql_pconnect | This function will generate an E_DEPRECATED error. | |
| mysql_tablename | The mysql_tablename function is deprecated, and emits an E_DEPRECATED level error. | |
| 5.3.0 | mysql_db_query | This function now throws an E_DEPRECATED notice. |
| mysql_escape_string | This function now throws an E_DEPRECATED notice. | |
| 4.3.7 | mysql_list_tables | This function became deprecated. |
| 4.3.0 | mysql_escape_string | This function became deprecated, do not use this function. Instead, use mysql_real_escape_string. |
Predefined Constants
The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
It is possible to specify additional client flags for the mysql_connect() and mysql_pconnect() functions. The following constants are defined:
| Constant | Description |
|---|---|
MYSQL_CLIENT_COMPRESS |
Use compression protocol |
MYSQL_CLIENT_IGNORE_SPACE |
Allow space after function names |
MYSQL_CLIENT_INTERACTIVE |
Allow interactive_timeout seconds (instead of wait_timeout) of inactivity before closing the connection. |
MYSQL_CLIENT_SSL |
Use SSL encryption. This flag is only available with version 4.x of the MySQL client library or newer. Version 3.23.x is bundled both with PHP 4 and Windows binaries of PHP 5. |
The function mysql_fetch_array() uses a constant for the different types of result arrays. The following constants are defined:
| Constant | Description |
|---|---|
MYSQL_ASSOC |
Columns are returned into the array having the fieldname as the array index. |
MYSQL_BOTH |
Columns are returned into the array having both a numerical index and the fieldname as the array index. |
MYSQL_NUM |
Columns are returned into the array having a numerical index to the fields. This index starts with 0, the first field in the result. |
Examples
Table of Contents
MySQL extension overview example
This simple example shows how to connect, execute a query, print resulting rows and disconnect from a MySQL database.
Example #1 MySQL extension overview example
<?php
// Connecting, selecting database
$link = mysql_connect('mysql_host', 'mysql_user', 'mysql_password')
or die('Could not connect: ' . mysql_error());
echo 'Connected successfully';
mysql_select_db('my_database') or die('Could not select database');
// Performing SQL query
$query = 'SELECT * FROM my_table';
$result = mysql_query($query) or die('Query failed: ' . mysql_error());
// Printing results in HTML
echo "<table>\n";
while ($line = mysql_fetch_array($result, MYSQL_ASSOC)) {
echo "\t<tr>\n";
foreach ($line as $col_value) {
echo "\t\t<td>$col_value</td>\n";
}
echo "\t</tr>\n";
}
echo "</table>\n";
// Free resultset
mysql_free_result($result);
// Closing connection
mysql_close($link);
?>
MySQL Functions
Notes
Note:
Most MySQL functions accept
link_identifieras the last optional parameter. If it is not provided, last opened connection is used. If it doesn't exist, connection is tried to establish with default parameters defined in php.ini. If it is not successful, functions returnFALSE.
mysql_affected_rows
(PHP 4, PHP 5)
mysql_affected_rows — Get number of affected rows in previous MySQL operation
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$link_identifier = NULL
] ) : int
Get the number of affected rows by the last INSERT, UPDATE, REPLACE
or DELETE query associated with link_identifier.
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns the number of affected rows on success, and -1 if the last query failed.
If the last query was a DELETE query with no WHERE clause, all of the records will have been deleted from the table but this function will return zero with MySQL versions prior to 4.1.2.
When using UPDATE, MySQL will not update columns where the new value is the same as the old value. This creates the possibility that mysql_affected_rows() may not actually equal the number of rows matched, only the number of rows that were literally affected by the query.
The REPLACE statement first deletes the record with the same primary key and then inserts the new record. This function returns the number of deleted records plus the number of inserted records.
In the case of "INSERT ... ON DUPLICATE KEY UPDATE" queries, the
return value will be 1 if an insert was performed,
or 2 for an update of an existing row.
Examples
Example #1 mysql_affected_rows() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');
/* this should return the correct numbers of deleted records */
mysql_query('DELETE FROM mytable WHERE id < 10');
printf("Records deleted: %d\n", mysql_affected_rows());
/* with a where clause that is never true, it should return 0 */
mysql_query('DELETE FROM mytable WHERE 0');
printf("Records deleted: %d\n", mysql_affected_rows());
?>
The above example will output something similar to:
Records deleted: 10 Records deleted: 0
Example #2 mysql_affected_rows() example using transactions
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');
/* Update records */
mysql_query("UPDATE mytable SET used=1 WHERE id < 10");
printf ("Updated records: %d\n", mysql_affected_rows());
mysql_query("COMMIT");
?>
The above example will output something similar to:
Updated Records: 10
Notes
Note: Transactions
If you are using transactions, you need to call mysql_affected_rows() after your INSERT, UPDATE, or DELETE query, not after the COMMIT.
Note: SELECT Statements
To retrieve the number of rows returned by a SELECT, it is possible to use mysql_num_rows().
Note: Cascaded Foreign Keys
mysql_affected_rows() does not count rows affected implicitly through the use of ON DELETE CASCADE and/or ON UPDATE CASCADE in foreign key constraints.
See Also
- mysql_num_rows() - Get number of rows in result
- mysql_info() - Get information about the most recent query
mysql_client_encoding
(PHP 4 >= 4.3.0, PHP 5)
mysql_client_encoding — Returns the name of the character set
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$link_identifier = NULL
] ) : string
Retrieves the character_set variable from MySQL.
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns the default character set name for the current connection.
Examples
Example #1 mysql_client_encoding() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$charset = mysql_client_encoding($link);
echo "The current character set is: $charset\n";
?>
The above example will output something similar to:
The current character set is: latin1
See Also
- mysql_set_charset() - Sets the client character set
- mysql_real_escape_string() - Escapes special characters in a string for use in an SQL statement
mysql_close
(PHP 4, PHP 5)
mysql_close — Close MySQL connection
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_close()
- PDO: Assign the value of
NULLto the PDO object
Description
$link_identifier = NULL
] ) : bool
mysql_close() closes the non-persistent connection to
the MySQL server that's associated with the specified link identifier. If
link_identifier isn't specified, the last opened
link is used.
Open non-persistent MySQL connections and result sets are automatically destroyed when a PHP script finishes its execution. So, while explicitly closing open connections and freeing result sets is optional, doing so is recommended. This will immediately return resources to PHP and MySQL, which can improve performance. For related information, see freeing resources
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 mysql_close() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>
The above example will output:
Connected successfully
Notes
Note:
mysql_close() will not close persistent links created by mysql_pconnect(). For additional details, see the manual page on persistent connections.
See Also
- mysql_connect() - Open a connection to a MySQL Server
- mysql_free_result() - Free result memory
mysql_connect
(PHP 4, PHP 5)
mysql_connect — Open a connection to a MySQL Server
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$server = ini_get("mysql.default_host")
[, string $username = ini_get("mysql.default_user")
[, string $password = ini_get("mysql.default_password")
[, bool $new_link = FALSE
[, int $client_flags = 0
]]]]] ) : resourceOpens or reuses a connection to a MySQL server.
Parameters
-
server -
The MySQL server. It can also include a port number. e.g. "hostname:port" or a path to a local socket e.g. ":/path/to/socket" for the localhost.
If the PHP directive mysql.default_host is undefined (default), then the default value is 'localhost:3306'. In SQL safe mode, this parameter is ignored and value 'localhost:3306' is always used.
-
username -
The username. Default value is defined by mysql.default_user. In SQL safe mode, this parameter is ignored and the name of the user that owns the server process is used.
-
password -
The password. Default value is defined by mysql.default_password. In SQL safe mode, this parameter is ignored and empty password is used.
-
new_link -
If a second call is made to mysql_connect() with the same arguments, no new link will be established, but instead, the link identifier of the already opened link will be returned. The
new_linkparameter modifies this behavior and makes mysql_connect() always open a new link, even if mysql_connect() was called before with the same parameters. In SQL safe mode, this parameter is ignored. -
client_flags -
The
client_flagsparameter can be a combination of the following constants: 128 (enableLOAD DATA LOCALhandling),MYSQL_CLIENT_SSL,MYSQL_CLIENT_COMPRESS,MYSQL_CLIENT_IGNORE_SPACEorMYSQL_CLIENT_INTERACTIVE. Read the section about MySQL client constants for further information. In SQL safe mode, this parameter is ignored.
Return Values
Returns a MySQL link identifier on success or FALSE on failure.
Changelog
| Version | Description |
|---|---|
| 5.5.0 |
This function will generate an E_DEPRECATED
error.
|
Examples
Example #1 mysql_connect() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>
Example #2 mysql_connect() example using hostname:port syntax
<?php
// we connect to example.com and port 3307
$link = mysql_connect('example.com:3307', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
// we connect to localhost at port 3307
$link = mysql_connect('127.0.0.1:3307', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>
Example #3 mysql_connect() example using ":/path/to/socket" syntax
<?php
// we connect to localhost and socket e.g. /tmp/mysql.sock
// variant 1: omit localhost
$link = mysql_connect(':/tmp/mysql', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
// variant 2: with localhost
$link = mysql_connect('localhost:/tmp/mysql.sock', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>
Notes
Note:
Whenever you specify "localhost" or "localhost:port" as server, the MySQL client library will override this and try to connect to a local socket (named pipe on Windows). If you want to use TCP/IP, use "127.0.0.1" instead of "localhost". If the MySQL client library tries to connect to the wrong local socket, you should set the correct path as in your PHP configuration and leave the server field blank.
Note:
The link to the server will be closed as soon as the execution of the script ends, unless it's closed earlier by explicitly calling mysql_close().
Note:
Error "Can't create TCP/IP socket (10106)" usually means that the variables_order configure directive doesn't contain character
E. On Windows, if the environment is not copied theSYSTEMROOTenvironment variable won't be available and PHP will have problems loading Winsock.
See Also
- mysql_pconnect() - Open a persistent connection to a MySQL server
- mysql_close() - Close MySQL connection
mysql_create_db
(PHP 4, PHP 5)
mysql_create_db — Create a MySQL database
This function was deprecated in PHP 4.3.0, and it and the entire original MySQL extension was removed in PHP 7.0.0. Instead, use either the actively developed MySQLi or PDO_MySQL extensions. See also the MySQL: choosing an API guide and its related FAQ entry for additional information. Alternatives to this function include:
Description
$database_name
[, resource $link_identifier = NULL
] ) : boolmysql_create_db() attempts to create a new database on the server associated with the specified link identifier.
Parameters
-
database_name -
The name of the database being created.
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 mysql_create_db() alternative example
The function mysql_create_db() is deprecated. It is
preferable to use mysql_query() to issue an sql
CREATE DATABASE statement instead.
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
$sql = 'CREATE DATABASE my_db';
if (mysql_query($sql, $link)) {
echo "Database my_db created successfully\n";
} else {
echo 'Error creating database: ' . mysql_error() . "\n";
}
?>
The above example will output something similar to:
Database my_db created successfully
Notes
Note:
For backward compatibility, the following deprecated alias may be used: mysql_createdb()
Note:
This function will not be available if the MySQL extension was built against a MySQL 4.x client library.
mysql_data_seek
(PHP 4, PHP 5)
mysql_data_seek — Move internal result pointer
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_data_seek()
PDO::FETCH_ORI_ABS
Description
$result
, int $row_number
) : boolmysql_data_seek() moves the internal row pointer of the MySQL result associated with the specified result identifier to point to the specified row number. The next call to a MySQL fetch function, such as mysql_fetch_assoc(), would return that row.
row_number starts at 0. The
row_number should be a value in the range from 0 to
mysql_num_rows() - 1. However if the result set
is empty (mysql_num_rows() == 0), a seek to 0 will
fail with an E_WARNING and
mysql_data_seek() will return FALSE.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
-
row_number -
The desired row number of the new result pointer.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 mysql_data_seek() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
$db_selected = mysql_select_db('sample_db');
if (!$db_selected) {
die('Could not select database: ' . mysql_error());
}
$query = 'SELECT last_name, first_name FROM friends';
$result = mysql_query($query);
if (!$result) {
die('Query failed: ' . mysql_error());
}
/* fetch rows in reverse order */
for ($i = mysql_num_rows($result) - 1; $i >= 0; $i--) {
if (!mysql_data_seek($result, $i)) {
echo "Cannot seek to row $i: " . mysql_error() . "\n";
continue;
}
if (!($row = mysql_fetch_assoc($result))) {
continue;
}
echo $row['last_name'] . ' ' . $row['first_name'] . "<br />\n";
}
mysql_free_result($result);
?>
Notes
Note:
The function mysql_data_seek() can be used in conjunction only with mysql_query(), not with mysql_unbuffered_query().
See Also
- mysql_query() - Send a MySQL query
- mysql_num_rows() - Get number of rows in result
- mysql_fetch_row() - Get a result row as an enumerated array
- mysql_fetch_assoc() - Fetch a result row as an associative array
- mysql_fetch_array() - Fetch a result row as an associative array, a numeric array, or both
- mysql_fetch_object() - Fetch a result row as an object
mysql_db_name
(PHP 4, PHP 5)
mysql_db_name — Retrieves database name from the call to mysql_list_dbs()
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- Query:
SELECT DATABASE()
Description
Retrieve the database name from a call to mysql_list_dbs().
Parameters
-
result -
The result pointer from a call to mysql_list_dbs().
-
row -
The index into the result set.
-
field -
The field name.
Return Values
Returns the database name on success, and FALSE on failure. If FALSE
is returned, use mysql_error() to determine the nature
of the error.
Changelog
| Version | Description |
|---|---|
| 5.5.0 |
The mysql_list_dbs() function is deprecated,
and emits an E_DEPRECATED level error.
|
Examples
Example #1 mysql_db_name() example
<?php
error_reporting(E_ALL);
$link = mysql_connect('dbhost', 'username', 'password');
$db_list = mysql_list_dbs($link);
$i = 0;
$cnt = mysql_num_rows($db_list);
while ($i < $cnt) {
echo mysql_db_name($db_list, $i) . "\n";
$i++;
}
?>
Notes
Note:
For backward compatibility, the following deprecated alias may be used: mysql_dbname()
See Also
- mysql_list_dbs() - List databases available on a MySQL server
- mysql_tablename() - Get table name of field
mysql_db_query
(PHP 4, PHP 5)
mysql_db_query — Selects a database and executes a query on it
This function was deprecated in PHP 5.3.0, and it and the entire original MySQL extension was removed in PHP 7.0.0. Instead, use either the actively developed MySQLi or PDO_MySQL extensions. See also the MySQL: choosing an API guide and its related FAQ entry for additional information. Alternatives to this function include:
- mysqli_select_db() then the query
- PDO::__construct()
Description
$database
, string $query
[, resource $link_identifier = NULL
] ) : resourcemysql_db_query() selects a database, and executes a query on it.
Parameters
-
database -
The name of the database that will be selected.
-
query -
The MySQL query.
Data inside the query should be properly escaped.
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns a positive MySQL result resource to the query result,
or FALSE on error. The function also returns TRUE/FALSE for
INSERT/UPDATE/DELETE
queries to indicate success/failure.
Changelog
| Version | Description |
|---|---|
| 5.3.0 | This function now throws an E_DEPRECATED notice. |
Examples
Example #1 mysql_db_query() alternative example
<?php
if (!$link = mysql_connect('mysql_host', 'mysql_user', 'mysql_password')) {
echo 'Could not connect to mysql';
exit;
}
if (!mysql_select_db('mysql_dbname', $link)) {
echo 'Could not select database';
exit;
}
$sql = 'SELECT foo FROM bar WHERE id = 42';
$result = mysql_query($sql, $link);
if (!$result) {
echo "DB Error, could not query the database\n";
echo 'MySQL Error: ' . mysql_error();
exit;
}
while ($row = mysql_fetch_assoc($result)) {
echo $row['foo'];
}
mysql_free_result($result);
?>
Notes
Note:
Be aware that this function does NOT switch back to the database you were connected before. In other words, you can't use this function to temporarily run a sql query on another database, you would have to manually switch back. Users are strongly encouraged to use the
database.tablesyntax in their sql queries or mysql_select_db() instead of this function.
mysql_drop_db
(PHP 4, PHP 5)
mysql_drop_db — Drop (delete) a MySQL database
This function was deprecated in PHP 4.3.0, and it and the entire original MySQL extension was removed in PHP 7.0.0. Instead, use either the actively developed MySQLi or PDO_MySQL extensions. See also the MySQL: choosing an API guide and its related FAQ entry for additional information. Alternatives to this function include:
- Execute a
DROP DATABASEquery
Description
$database_name
[, resource $link_identifier = NULL
] ) : bool
mysql_drop_db() attempts to drop (remove) an
entire database from the server associated with the specified
link identifier. This function is deprecated, it is preferable to use
mysql_query() to issue an sql
DROP DATABASE statement instead.
Parameters
-
database_name -
The name of the database that will be deleted.
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 mysql_drop_db() alternative example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
$sql = 'DROP DATABASE my_db';
if (mysql_query($sql, $link)) {
echo "Database my_db was successfully dropped\n";
} else {
echo 'Error dropping database: ' . mysql_error() . "\n";
}
?>
Notes
This function will not be available if the MySQL extension was built against a MySQL 4.x client library.
Note:
For backward compatibility, the following deprecated alias may be used: mysql_dropdb()
mysql_errno
(PHP 4, PHP 5)
mysql_errno — Returns the numerical value of the error message from previous MySQL operation
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$link_identifier = NULL
] ) : intReturns the error number from the last MySQL function.
Errors coming back from the MySQL database backend no longer issue warnings. Instead, use mysql_errno() to retrieve the error code. Note that this function only returns the error code from the most recently executed MySQL function (not including mysql_error() and mysql_errno()), so if you want to use it, make sure you check the value before calling another MySQL function.
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns the error number from the last MySQL function, or
0 (zero) if no error occurred.
Examples
Example #1 mysql_errno() example
<?php
$link = mysql_connect("localhost", "mysql_user", "mysql_password");
if (!mysql_select_db("nonexistentdb", $link)) {
echo mysql_errno($link) . ": " . mysql_error($link). "\n";
}
mysql_select_db("kossu", $link);
if (!mysql_query("SELECT * FROM nonexistenttable", $link)) {
echo mysql_errno($link) . ": " . mysql_error($link) . "\n";
}
?>
The above example will output something similar to:
1049: Unknown database 'nonexistentdb' 1146: Table 'kossu.nonexistenttable' doesn't exist
See Also
- mysql_error() - Returns the text of the error message from previous MySQL operation
- » MySQL error codes
mysql_error
(PHP 4, PHP 5)
mysql_error — Returns the text of the error message from previous MySQL operation
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$link_identifier = NULL
] ) : stringReturns the error text from the last MySQL function. Errors coming back from the MySQL database backend no longer issue warnings. Instead, use mysql_error() to retrieve the error text. Note that this function only returns the error text from the most recently executed MySQL function (not including mysql_error() and mysql_errno()), so if you want to use it, make sure you check the value before calling another MySQL function.
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns the error text from the last MySQL function, or
'' (empty string) if no error occurred.
Examples
Example #1 mysql_error() example
<?php
$link = mysql_connect("localhost", "mysql_user", "mysql_password");
mysql_select_db("nonexistentdb", $link);
echo mysql_errno($link) . ": " . mysql_error($link). "\n";
mysql_select_db("kossu", $link);
mysql_query("SELECT * FROM nonexistenttable", $link);
echo mysql_errno($link) . ": " . mysql_error($link) . "\n";
?>
The above example will output something similar to:
1049: Unknown database 'nonexistentdb' 1146: Table 'kossu.nonexistenttable' doesn't exist
See Also
- mysql_errno() - Returns the numerical value of the error message from previous MySQL operation
- » MySQL error codes
mysql_escape_string
(PHP 4 >= 4.0.3, PHP 5)
mysql_escape_string — Escapes a string for use in a mysql_query
This function was deprecated in PHP 4.3.0, and it and the entire original MySQL extension was removed in PHP 7.0.0. Instead, use either the actively developed MySQLi or PDO_MySQL extensions. See also the MySQL: choosing an API guide and its related FAQ entry for additional information. Alternatives to this function include:
Description
$unescaped_string
) : string
This function will escape the unescaped_string,
so that it is safe to place it in a mysql_query().
This function is deprecated.
This function is identical to mysql_real_escape_string() except that mysql_real_escape_string() takes a connection handler and escapes the string according to the current character set. mysql_escape_string() does not take a connection argument and does not respect the current charset setting.
Parameters
-
unescaped_string -
The string that is to be escaped.
Return Values
Returns the escaped string.
Changelog
| Version | Description |
|---|---|
| 5.3.0 | This function now throws an E_DEPRECATED notice. |
| 4.3.0 | This function became deprecated, do not use this function. Instead, use mysql_real_escape_string(). |
Examples
Example #1 mysql_escape_string() example
<?php
$item = "Zak's Laptop";
$escaped_item = mysql_escape_string($item);
printf("Escaped string: %s\n", $escaped_item);
?>
The above example will output:
Escaped string: Zak\'s Laptop
Notes
Note:
mysql_escape_string() does not escape
%and_.
See Also
- mysql_real_escape_string() - Escapes special characters in a string for use in an SQL statement
- addslashes() - Quote string with slashes
- The magic_quotes_gpc directive.
mysql_fetch_array
(PHP 4, PHP 5)
mysql_fetch_array — Fetch a result row as an associative array, a numeric array, or both
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$result
[, int $result_type = MYSQL_BOTH
] ) : arrayReturns an array that corresponds to the fetched row and moves the internal data pointer ahead.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
-
result_type -
The type of array that is to be fetched. It's a constant and can take the following values:
MYSQL_ASSOC,MYSQL_NUM, andMYSQL_BOTH.
Return Values
Returns an array of strings that corresponds to the fetched row, or FALSE
if there are no more rows. The type of returned array depends on
how result_type is defined. By using
MYSQL_BOTH (default), you'll get an array with both
associative and number indices. Using MYSQL_ASSOC, you
only get associative indices (as mysql_fetch_assoc()
works), using MYSQL_NUM, you only get number indices
(as mysql_fetch_row() works).
If two or more columns of the result have the same field names, the last column will take precedence. To access the other column(s) of the same name, you must use the numeric index of the column or make an alias for the column. For aliased columns, you cannot access the contents with the original column name.
Examples
Example #1 Query with aliased duplicate field names
SELECT table1.field AS foo, table2.field AS bar FROM table1, table2
Example #2 mysql_fetch_array() with MYSQL_NUM
<?php
mysql_connect("localhost", "mysql_user", "mysql_password") or
die("Could not connect: " . mysql_error());
mysql_select_db("mydb");
$result = mysql_query("SELECT id, name FROM mytable");
while ($row = mysql_fetch_array($result, MYSQL_NUM)) {
printf("ID: %s Name: %s", $row[0], $row[1]);
}
mysql_free_result($result);
?>
Example #3 mysql_fetch_array() with MYSQL_ASSOC
<?php
mysql_connect("localhost", "mysql_user", "mysql_password") or
die("Could not connect: " . mysql_error());
mysql_select_db("mydb");
$result = mysql_query("SELECT id, name FROM mytable");
while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
printf("ID: %s Name: %s", $row["id"], $row["name"]);
}
mysql_free_result($result);
?>
Example #4 mysql_fetch_array() with MYSQL_BOTH
<?php
mysql_connect("localhost", "mysql_user", "mysql_password") or
die("Could not connect: " . mysql_error());
mysql_select_db("mydb");
$result = mysql_query("SELECT id, name FROM mytable");
while ($row = mysql_fetch_array($result, MYSQL_BOTH)) {
printf ("ID: %s Name: %s", $row[0], $row["name"]);
}
mysql_free_result($result);
?>
Notes
Note: Performance
An important thing to note is that using mysql_fetch_array() is not significantly slower than using mysql_fetch_row(), while it provides a significant added value.
Note: Field names returned by this function are case-sensitive.
Note: This function sets NULL fields to the PHP
NULLvalue.
See Also
- mysql_fetch_row() - Get a result row as an enumerated array
- mysql_fetch_assoc() - Fetch a result row as an associative array
- mysql_data_seek() - Move internal result pointer
- mysql_query() - Send a MySQL query
mysql_fetch_assoc
(PHP 4 >= 4.0.3, PHP 5)
mysql_fetch_assoc — Fetch a result row as an associative array
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$result
) : arrayReturns an associative array that corresponds to the fetched row and moves the internal data pointer ahead. mysql_fetch_assoc() is equivalent to calling mysql_fetch_array() with MYSQL_ASSOC for the optional second parameter. It only returns an associative array.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
Return Values
Returns an associative array of strings that corresponds to the fetched row, or
FALSE if there are no more rows.
If two or more columns of the result have the same field names, the last column will take precedence. To access the other column(s) of the same name, you either need to access the result with numeric indices by using mysql_fetch_row() or add alias names. See the example at the mysql_fetch_array() description about aliases.
Examples
Example #1 An expanded mysql_fetch_assoc() example
<?php
$conn = mysql_connect("localhost", "mysql_user", "mysql_password");
if (!$conn) {
echo "Unable to connect to DB: " . mysql_error();
exit;
}
if (!mysql_select_db("mydbname")) {
echo "Unable to select mydbname: " . mysql_error();
exit;
}
$sql = "SELECT id as userid, fullname, userstatus
FROM sometable
WHERE userstatus = 1";
$result = mysql_query($sql);
if (!$result) {
echo "Could not successfully run query ($sql) from DB: " . mysql_error();
exit;
}
if (mysql_num_rows($result) == 0) {
echo "No rows found, nothing to print so am exiting";
exit;
}
// While a row of data exists, put that row in $row as an associative array
// Note: If you're expecting just one row, no need to use a loop
// Note: If you put extract($row); inside the following loop, you'll
// then create $userid, $fullname, and $userstatus
while ($row = mysql_fetch_assoc($result)) {
echo $row["userid"];
echo $row["fullname"];
echo $row["userstatus"];
}
mysql_free_result($result);
?>
Notes
Note: Performance
An important thing to note is that using mysql_fetch_assoc() is not significantly slower than using mysql_fetch_row(), while it provides a significant added value.
Note: Field names returned by this function are case-sensitive.
Note: This function sets NULL fields to the PHP
NULLvalue.
See Also
- mysql_fetch_row() - Get a result row as an enumerated array
- mysql_fetch_array() - Fetch a result row as an associative array, a numeric array, or both
- mysql_data_seek() - Move internal result pointer
- mysql_query() - Send a MySQL query
- mysql_error() - Returns the text of the error message from previous MySQL operation
mysql_fetch_field
(PHP 4, PHP 5)
mysql_fetch_field — Get column information from a result and return as an object
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$result
[, int $field_offset = 0
] ) : objectReturns an object containing field information. This function can be used to obtain information about fields in the provided query result.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
-
field_offset -
The numerical field offset. If the field offset is not specified, the next field that was not yet retrieved by this function is retrieved. The
field_offsetstarts at0.
Return Values
Returns an object containing field information. The properties of the object are:
- name - column name
- table - name of the table the column belongs to, which is the alias name if one is defined
- max_length - maximum length of the column
-
not_null - 1 if the column cannot be
NULL - primary_key - 1 if the column is a primary key
- unique_key - 1 if the column is a unique key
- multiple_key - 1 if the column is a non-unique key
- numeric - 1 if the column is numeric
- blob - 1 if the column is a BLOB
- type - the type of the column
- unsigned - 1 if the column is unsigned
- zerofill - 1 if the column is zero-filled
Examples
Example #1 mysql_fetch_field() example
<?php
$conn = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$conn) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db('database');
$result = mysql_query('select * from table');
if (!$result) {
die('Query failed: ' . mysql_error());
}
/* get column metadata */
$i = 0;
while ($i < mysql_num_fields($result)) {
echo "Information for column $i:<br />\n";
$meta = mysql_fetch_field($result, $i);
if (!$meta) {
echo "No information available<br />\n";
}
echo "<pre>
blob: $meta->blob
max_length: $meta->max_length
multiple_key: $meta->multiple_key
name: $meta->name
not_null: $meta->not_null
numeric: $meta->numeric
primary_key: $meta->primary_key
table: $meta->table
type: $meta->type
unique_key: $meta->unique_key
unsigned: $meta->unsigned
zerofill: $meta->zerofill
</pre>";
$i++;
}
mysql_free_result($result);
?>
Notes
Note: Field names returned by this function are case-sensitive.
Note:
If field or tablenames are aliased in the SQL query the aliased name will be returned. The original name can be retrieved for instance by using mysqli_result::fetch_field().
mysql_fetch_lengths
(PHP 4, PHP 5)
mysql_fetch_lengths — Get the length of each output in a result
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$result
) : arrayReturns an array that corresponds to the lengths of each field in the last row fetched by MySQL.
mysql_fetch_lengths() stores the lengths of each result column in the last row returned by mysql_fetch_row(), mysql_fetch_assoc(), mysql_fetch_array(), and mysql_fetch_object() in an array, starting at offset 0.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
Return Values
An array of lengths on success or FALSE on failure.
Examples
Example #1 A mysql_fetch_lengths() example
<?php
$result = mysql_query("SELECT id,email FROM people WHERE id = '42'");
if (!$result) {
echo 'Could not run query: ' . mysql_error();
exit;
}
$row = mysql_fetch_assoc($result);
$lengths = mysql_fetch_lengths($result);
print_r($row);
print_r($lengths);
?>
The above example will output something similar to:
Array
(
[id] => 42
[email] => user@example.com
)
Array
(
[0] => 2
[1] => 16
)
See Also
- mysql_field_len() - Returns the length of the specified field
- mysql_fetch_row() - Get a result row as an enumerated array
- strlen() - Get string length
mysql_fetch_object
(PHP 4, PHP 5)
mysql_fetch_object — Fetch a result row as an object
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$result
[, string $class_name
[, array $params
]] ) : objectReturns an object with properties that correspond to the fetched row and moves the internal data pointer ahead.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
-
class_name -
The name of the class to instantiate, set the properties of and return. If not specified, a stdClass object is returned.
-
params -
An optional array of parameters to pass to the constructor for
class_nameobjects.
Return Values
Returns an object with string properties that correspond to the
fetched row, or FALSE if there are no more rows.
Examples
Example #1 mysql_fetch_object() example
<?php
mysql_connect("hostname", "user", "password");
mysql_select_db("mydb");
$result = mysql_query("select * from mytable");
while ($row = mysql_fetch_object($result)) {
echo $row->user_id;
echo $row->fullname;
}
mysql_free_result($result);
?>
Example #2 mysql_fetch_object() example
<?php
class foo {
public $name;
}
mysql_connect("hostname", "user", "password");
mysql_select_db("mydb");
$result = mysql_query("select name from mytable limit 1");
$obj = mysql_fetch_object($result, 'foo');
var_dump($obj);
?>
Notes
Note: Performance
Speed-wise, the function is identical to mysql_fetch_array(), and almost as quick as mysql_fetch_row() (the difference is insignificant).
Note:
mysql_fetch_object() is similar to mysql_fetch_array(), with one difference - an object is returned, instead of an array. Indirectly, that means that you can only access the data by the field names, and not by their offsets (numbers are illegal property names).
Note: Field names returned by this function are case-sensitive.
Note: This function sets NULL fields to the PHP
NULLvalue.
See Also
- mysql_fetch_array() - Fetch a result row as an associative array, a numeric array, or both
- mysql_fetch_assoc() - Fetch a result row as an associative array
- mysql_fetch_row() - Get a result row as an enumerated array
- mysql_data_seek() - Move internal result pointer
- mysql_query() - Send a MySQL query
mysql_fetch_row
(PHP 4, PHP 5)
mysql_fetch_row — Get a result row as an enumerated array
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$result
) : arrayReturns a numerical array that corresponds to the fetched row and moves the internal data pointer ahead.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
Return Values
Returns an numerical array of strings that corresponds to the fetched row, or
FALSE if there are no more rows.
mysql_fetch_row() fetches one row of data from the result associated with the specified result identifier. The row is returned as an array. Each result column is stored in an array offset, starting at offset 0.
Examples
Example #1 Fetching one row with mysql_fetch_row()
<?php
$result = mysql_query("SELECT id,email FROM people WHERE id = '42'");
if (!$result) {
echo 'Could not run query: ' . mysql_error();
exit;
}
$row = mysql_fetch_row($result);
echo $row[0]; // 42
echo $row[1]; // the email value
?>
Notes
Note: This function sets NULL fields to the PHP
NULLvalue.
See Also
- mysql_fetch_array() - Fetch a result row as an associative array, a numeric array, or both
- mysql_fetch_assoc() - Fetch a result row as an associative array
- mysql_fetch_object() - Fetch a result row as an object
- mysql_data_seek() - Move internal result pointer
- mysql_fetch_lengths() - Get the length of each output in a result
- mysql_result() - Get result data
mysql_field_flags
(PHP 4, PHP 5)
mysql_field_flags — Get the flags associated with the specified field in a result
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_fetch_field_direct() [flags]
- PDOStatement::getColumnMeta() [flags]
Description
$result
, int $field_offset
) : stringmysql_field_flags() returns the field flags of the specified field. The flags are reported as a single word per flag separated by a single space, so that you can split the returned value using explode().
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
-
field_offset -
The numerical field offset. The
field_offsetstarts at0. Iffield_offsetdoes not exist, an error of levelE_WARNINGis also issued.
Return Values
Returns a string of flags associated with the result or FALSE on failure.
The following flags are reported, if your version of MySQL
is current enough to support them: "not_null",
"primary_key", "unique_key",
"multiple_key", "blob",
"unsigned", "zerofill",
"binary", "enum",
"auto_increment" and "timestamp".
Examples
Example #1 A mysql_field_flags() example
<?php
$result = mysql_query("SELECT id,email FROM people WHERE id = '42'");
if (!$result) {
echo 'Could not run query: ' . mysql_error();
exit;
}
$flags = mysql_field_flags($result, 0);
echo $flags;
print_r(explode(' ', $flags));
?>
The above example will output something similar to:
not_null primary_key auto_increment
Array
(
[0] => not_null
[1] => primary_key
[2] => auto_increment
)
Notes
Note:
For backward compatibility, the following deprecated alias may be used: mysql_fieldflags()
See Also
- mysql_field_type() - Get the type of the specified field in a result
- mysql_field_len() - Returns the length of the specified field
mysql_field_len
(PHP 4, PHP 5)
mysql_field_len — Returns the length of the specified field
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_fetch_field_direct() [length]
- PDOStatement::getColumnMeta() [len]
Description
$result
, int $field_offset
) : intmysql_field_len() returns the length of the specified field.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
-
field_offset -
The numerical field offset. The
field_offsetstarts at0. Iffield_offsetdoes not exist, an error of levelE_WARNINGis also issued.
Return Values
The length of the specified field index on success or FALSE on failure.
Examples
Example #1 mysql_field_len() example
<?php
$result = mysql_query("SELECT id,email FROM people WHERE id = '42'");
if (!$result) {
echo 'Could not run query: ' . mysql_error();
exit;
}
// Will get the length of the id field as specified in the database
// schema.
$length = mysql_field_len($result, 0);
echo $length;
?>
Notes
Note:
For backward compatibility, the following deprecated alias may be used: mysql_fieldlen()
See Also
- mysql_fetch_lengths() - Get the length of each output in a result
- strlen() - Get string length
mysql_field_name
(PHP 4, PHP 5)
mysql_field_name — Get the name of the specified field in a result
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_fetch_field_direct() [name] or [orgname]
- PDOStatement::getColumnMeta() [name]
Description
$result
, int $field_offset
) : stringmysql_field_name() returns the name of the specified field index.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
-
field_offset -
The numerical field offset. The
field_offsetstarts at0. Iffield_offsetdoes not exist, an error of levelE_WARNINGis also issued.
Return Values
The name of the specified field index on success or FALSE on failure.
Examples
Example #1 mysql_field_name() example
<?php
/* The users table consists of three fields:
* user_id
* username
* password.
*/
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect to MySQL server: ' . mysql_error());
}
$dbname = 'mydb';
$db_selected = mysql_select_db($dbname, $link);
if (!$db_selected) {
die("Could not set $dbname: " . mysql_error());
}
$res = mysql_query('select * from users', $link);
echo mysql_field_name($res, 0) . "\n";
echo mysql_field_name($res, 2);
?>
The above example will output:
user_id password
Notes
Note: Field names returned by this function are case-sensitive.
Note:
For backward compatibility, the following deprecated alias may be used: mysql_fieldname()
See Also
- mysql_field_type() - Get the type of the specified field in a result
- mysql_field_len() - Returns the length of the specified field
mysql_field_seek
(PHP 4, PHP 5)
mysql_field_seek — Set result pointer to a specified field offset
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_field_seek()
-
PDOStatement::fetch() using the
cursor_orientationandoffsetparameters
Description
$result
, int $field_offset
) : boolSeeks to the specified field offset. If the next call to mysql_fetch_field() doesn't include a field offset, the field offset specified in mysql_field_seek() will be returned.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
-
field_offset -
The numerical field offset. The
field_offsetstarts at0. Iffield_offsetdoes not exist, an error of levelE_WARNINGis also issued.
Return Values
Returns TRUE on success or FALSE on failure.
mysql_field_table
(PHP 4, PHP 5)
mysql_field_table — Get name of the table the specified field is in
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_fetch_field_direct() [table] or [orgtable]
- PDOStatement::getColumnMeta() [table]
Description
$result
, int $field_offset
) : stringReturns the name of the table that the specified field is in.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
-
field_offset -
The numerical field offset. The
field_offsetstarts at0. Iffield_offsetdoes not exist, an error of levelE_WARNINGis also issued.
Return Values
The name of the table on success.
Examples
Example #1 A mysql_field_table() example
<?php
$query = "SELECT account.*, country.* FROM account, country WHERE country.name = 'Portugal' AND account.country_id = country.id";
// get the result from the DB
$result = mysql_query($query);
// Lists the table name and then the field name
for ($i = 0; $i < mysql_num_fields($result); ++$i) {
$table = mysql_field_table($result, $i);
$field = mysql_field_name($result, $i);
echo "$table: $field\n";
}
?>
Notes
Note:
For backward compatibility, the following deprecated alias may be used: mysql_fieldtable()
mysql_field_type
(PHP 4, PHP 5)
mysql_field_type — Get the type of the specified field in a result
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_fetch_field_direct() [type]
- PDOStatement::getColumnMeta() [driver:decl_type] or [pdo_type]
Description
$result
, int $field_offset
) : stringmysql_field_type() is similar to the mysql_field_name() function. The arguments are identical, but the field type is returned instead.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
-
field_offset -
The numerical field offset. The
field_offsetstarts at0. Iffield_offsetdoes not exist, an error of levelE_WARNINGis also issued.
Return Values
The returned field type
will be one of "int", "real",
"string", "blob", and others as
detailed in the » MySQL
documentation.
Examples
Example #1 mysql_field_type() example
<?php
mysql_connect("localhost", "mysql_username", "mysql_password");
mysql_select_db("mysql");
$result = mysql_query("SELECT * FROM func");
$fields = mysql_num_fields($result);
$rows = mysql_num_rows($result);
$table = mysql_field_table($result, 0);
echo "Your '" . $table . "' table has " . $fields . " fields and " . $rows . " record(s)\n";
echo "The table has the following fields:\n";
for ($i=0; $i < $fields; $i++) {
$type = mysql_field_type($result, $i);
$name = mysql_field_name($result, $i);
$len = mysql_field_len($result, $i);
$flags = mysql_field_flags($result, $i);
echo $type . " " . $name . " " . $len . " " . $flags . "\n";
}
mysql_free_result($result);
mysql_close();
?>
The above example will output something similar to:
Your 'func' table has 4 fields and 1 record(s) The table has the following fields: string name 64 not_null primary_key binary int ret 1 not_null string dl 128 not_null string type 9 not_null enum
Notes
Note:
For backward compatibility, the following deprecated alias may be used: mysql_fieldtype()
See Also
- mysql_field_name() - Get the name of the specified field in a result
- mysql_field_len() - Returns the length of the specified field
mysql_free_result
(PHP 4, PHP 5)
mysql_free_result — Free result memory
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_free_result()
- Assign the value of
NULLto the PDO object, or PDOStatement::closeCursor()
Description
$result
) : bool
mysql_free_result() will free all memory
associated with the result identifier result.
mysql_free_result() only needs to be called if you are concerned about how much memory is being used for queries that return large result sets. All associated result memory is automatically freed at the end of the script's execution.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
Return Values
Returns TRUE on success or FALSE on failure.
If a non-resource is used for the result, an
error of level E_WARNING will be emitted. It's worth noting that
mysql_query() only returns a resource
for SELECT, SHOW, EXPLAIN, and DESCRIBE queries.
Examples
Example #1 A mysql_free_result() example
<?php
$result = mysql_query("SELECT id,email FROM people WHERE id = '42'");
if (!$result) {
echo 'Could not run query: ' . mysql_error();
exit;
}
/* Use the result, assuming we're done with it afterwards */
$row = mysql_fetch_assoc($result);
/* Now we free up the result and continue on with our script */
mysql_free_result($result);
echo $row['id'];
echo $row['email'];
?>
Notes
Note:
For backward compatibility, the following deprecated alias may be used: mysql_freeresult()
mysql_get_client_info
(PHP 4 >= 4.0.5, PHP 5)
mysql_get_client_info — Get MySQL client info
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
mysql_get_client_info() returns a string that represents the client library version.
Return Values
The MySQL client version.
Examples
Example #1 mysql_get_client_info() example
<?php
printf("MySQL client info: %s\n", mysql_get_client_info());
?>
The above example will output something similar to:
MySQL client info: 3.23.39
See Also
- mysql_get_host_info() - Get MySQL host info
- mysql_get_proto_info() - Get MySQL protocol info
- mysql_get_server_info() - Get MySQL server info
mysql_get_host_info
(PHP 4 >= 4.0.5, PHP 5)
mysql_get_host_info — Get MySQL host info
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$link_identifier = NULL
] ) : stringDescribes the type of connection in use for the connection, including the server host name.
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns a string describing the type of MySQL connection in use for the
connection or FALSE on failure.
Examples
Example #1 mysql_get_host_info() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
printf("MySQL host info: %s\n", mysql_get_host_info());
?>
The above example will output something similar to:
MySQL host info: Localhost via UNIX socket
See Also
- mysql_get_client_info() - Get MySQL client info
- mysql_get_proto_info() - Get MySQL protocol info
- mysql_get_server_info() - Get MySQL server info
mysql_get_proto_info
(PHP 4 >= 4.0.5, PHP 5)
mysql_get_proto_info — Get MySQL protocol info
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$link_identifier = NULL
] ) : intRetrieves the MySQL protocol.
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns the MySQL protocol on success or FALSE on failure.
Examples
Example #1 mysql_get_proto_info() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
printf("MySQL protocol version: %s\n", mysql_get_proto_info());
?>
The above example will output something similar to:
MySQL protocol version: 10
See Also
- mysql_get_client_info() - Get MySQL client info
- mysql_get_host_info() - Get MySQL host info
- mysql_get_server_info() - Get MySQL server info
mysql_get_server_info
(PHP 4 >= 4.0.5, PHP 5)
mysql_get_server_info — Get MySQL server info
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$link_identifier = NULL
] ) : stringRetrieves the MySQL server version.
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns the MySQL server version on success or FALSE on failure.
Examples
Example #1 mysql_get_server_info() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
printf("MySQL server version: %s\n", mysql_get_server_info());
?>
The above example will output something similar to:
MySQL server version: 4.0.1-alpha
See Also
- mysql_get_client_info() - Get MySQL client info
- mysql_get_host_info() - Get MySQL host info
- mysql_get_proto_info() - Get MySQL protocol info
- phpversion() - Gets the current PHP version
mysql_info
(PHP 4 >= 4.3.0, PHP 5)
mysql_info — Get information about the most recent query
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$link_identifier = NULL
] ) : stringReturns detailed information about the last query.
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns information about the statement on success, or FALSE on
failure. See the example below for which statements provide information,
and what the returned value may look like. Statements that are not listed
will return FALSE.
Examples
Example #1 Relevant MySQL Statements
Statements that return string values. The numbers are only for illustrating purpose; their values will correspond to the query.
INSERT INTO ... SELECT ... String format: Records: 23 Duplicates: 0 Warnings: 0 INSERT INTO ... VALUES (...),(...),(...)... String format: Records: 37 Duplicates: 0 Warnings: 0 LOAD DATA INFILE ... String format: Records: 42 Deleted: 0 Skipped: 0 Warnings: 0 ALTER TABLE String format: Records: 60 Duplicates: 0 Warnings: 0 UPDATE String format: Rows matched: 65 Changed: 65 Warnings: 0
Notes
Note:
mysql_info() returns a non-
FALSEvalue for the INSERT ... VALUES statement only if multiple value lists are specified in the statement.
See Also
- mysql_affected_rows() - Get number of affected rows in previous MySQL operation
- mysql_insert_id() - Get the ID generated in the last query
- mysql_stat() - Get current system status
mysql_insert_id
(PHP 4, PHP 5)
mysql_insert_id — Get the ID generated in the last query
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$link_identifier = NULL
] ) : intRetrieves the ID generated for an AUTO_INCREMENT column by the previous query (usually INSERT).
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
The ID generated for an AUTO_INCREMENT column by the previous
query on success, 0 if the previous
query does not generate an AUTO_INCREMENT value, or FALSE if
no MySQL connection was established.
Examples
Example #1 mysql_insert_id() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');
mysql_query("INSERT INTO mytable (product) values ('kossu')");
printf("Last inserted record has id %d\n", mysql_insert_id());
?>
Notes
mysql_insert_id() will convert the return type of the
native MySQL C API function mysql_insert_id() to a type
of long (named int in PHP). If your
AUTO_INCREMENT column has a column type of BIGINT (64 bits) the
conversion may result in an incorrect value. Instead, use the internal
MySQL SQL function LAST_INSERT_ID() in an SQL query. For more information
about PHP's maximum integer values, please see the
integer documentation.
Note:
Because mysql_insert_id() acts on the last performed query, be sure to call mysql_insert_id() immediately after the query that generates the value.
Note:
The value of the MySQL SQL function
LAST_INSERT_ID()always contains the most recently generated AUTO_INCREMENT value, and is not reset between queries.
See Also
- mysql_query() - Send a MySQL query
- mysql_info() - Get information about the most recent query
mysql_list_dbs
(PHP 4, PHP 5)
mysql_list_dbs — List databases available on a MySQL server
This function was deprecated in PHP 5.4.0, and it and the entire original MySQL extension was removed in PHP 7.0.0. Instead, use either the actively developed MySQLi or PDO_MySQL extensions. See also the MySQL: choosing an API guide and its related FAQ entry for additional information. Alternatives to this function include:
- SQL Query:
SHOW DATABASES
Description
$link_identifier = NULL
] ) : resourceReturns a result pointer containing the databases available from the current mysql daemon.
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns a result pointer resource on success, or FALSE on
failure. Use the mysql_tablename() function to traverse
this result pointer, or any function for result tables, such as
mysql_fetch_array().
Examples
Example #1 mysql_list_dbs() example
<?php
// Usage without mysql_list_dbs()
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$res = mysql_query("SHOW DATABASES");
while ($row = mysql_fetch_assoc($res)) {
echo $row['Database'] . "\n";
}
// Deprecated as of PHP 5.4.0
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$db_list = mysql_list_dbs($link);
while ($row = mysql_fetch_object($db_list)) {
echo $row->Database . "\n";
}
?>
The above example will output something similar to:
database1 database2 database3
Notes
Note:
For backward compatibility, the following deprecated alias may be used: mysql_listdbs()
See Also
- mysql_db_name() - Retrieves database name from the call to mysql_list_dbs
- mysql_select_db() - Select a MySQL database
mysql_list_fields
(PHP 4, PHP 5)
mysql_list_fields — List MySQL table fields
This function was deprecated in PHP 5.4.0, and it and the entire original MySQL extension was removed in PHP 7.0.0. Instead, use either the actively developed MySQLi or PDO_MySQL extensions. See also the MySQL: choosing an API guide and its related FAQ entry for additional information. Alternatives to this function include:
- SQL Query:
SHOW COLUMNS FROM sometable
Description
$database_name
, string $table_name
[, resource $link_identifier = NULL
] ) : resourceRetrieves information about the given table name.
This function is deprecated. It is preferable to use
mysql_query() to issue an SQL SHOW COLUMNS FROM
table [LIKE 'name'] statement instead.
Parameters
-
database_name -
The name of the database that's being queried.
-
table_name -
The name of the table that's being queried.
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
A result pointer resource on success, or FALSE on
failure.
The returned result can be used with mysql_field_flags(), mysql_field_len(), mysql_field_name() and mysql_field_type().
Examples
Example #1 Alternate to deprecated mysql_list_fields()
<?php
$result = mysql_query("SHOW COLUMNS FROM sometable");
if (!$result) {
echo 'Could not run query: ' . mysql_error();
exit;
}
if (mysql_num_rows($result) > 0) {
while ($row = mysql_fetch_assoc($result)) {
print_r($row);
}
}
?>
The above example will output something similar to:
Array
(
[Field] => id
[Type] => int(7)
[Null] =>
[Key] => PRI
[Default] =>
[Extra] => auto_increment
)
Array
(
[Field] => email
[Type] => varchar(100)
[Null] =>
[Key] =>
[Default] =>
[Extra] =>
)
Notes
Note:
For backward compatibility, the following deprecated alias may be used: mysql_listfields()
See Also
- mysql_field_flags() - Get the flags associated with the specified field in a result
- mysql_info() - Get information about the most recent query
mysql_list_processes
(PHP 4 >= 4.3.0, PHP 5)
mysql_list_processes — List MySQL processes
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$link_identifier = NULL
] ) : resourceRetrieves the current MySQL server threads.
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
A result pointer resource on success or FALSE on failure.
Examples
Example #1 mysql_list_processes() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$result = mysql_list_processes($link);
while ($row = mysql_fetch_assoc($result)){
printf("%s %s %s %s %s\n", $row["Id"], $row["Host"], $row["db"],
$row["Command"], $row["Time"]);
}
mysql_free_result($result);
?>
The above example will output something similar to:
1 localhost test Processlist 0 4 localhost mysql sleep 5
mysql_list_tables
(PHP 4, PHP 5)
mysql_list_tables — List tables in a MySQL database
This function was deprecated in PHP 4.3.0, and it and the entire original MySQL extension was removed in PHP 7.0.0. Instead, use either the actively developed MySQLi or PDO_MySQL extensions. See also the MySQL: choosing an API guide and its related FAQ entry for additional information. Alternatives to this function include:
- SQL Query:
SHOW TABLES FROM dbname
Description
$database
[, resource $link_identifier = NULL
] ) : resourceRetrieves a list of table names from a MySQL database.
This function is deprecated. It is preferable to use
mysql_query() to issue an SQL SHOW TABLES
[FROM db_name] [LIKE 'pattern'] statement instead.
Parameters
-
database -
The name of the database
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
A result pointer resource on success or FALSE on failure.
Use the mysql_tablename() function to traverse this result pointer, or any function for result tables, such as mysql_fetch_array().
Changelog
| Version | Description |
|---|---|
| 4.3.7 | This function became deprecated. |
Examples
Example #1 mysql_list_tables() alternative example
<?php
$dbname = 'mysql_dbname';
if (!mysql_connect('mysql_host', 'mysql_user', 'mysql_password')) {
echo 'Could not connect to mysql';
exit;
}
$sql = "SHOW TABLES FROM $dbname";
$result = mysql_query($sql);
if (!$result) {
echo "DB Error, could not list tables\n";
echo 'MySQL Error: ' . mysql_error();
exit;
}
while ($row = mysql_fetch_row($result)) {
echo "Table: {$row[0]}\n";
}
mysql_free_result($result);
?>
Notes
Note:
For backward compatibility, the following deprecated alias may be used: mysql_listtables()
See Also
- mysql_list_dbs() - List databases available on a MySQL server
- mysql_tablename() - Get table name of field
mysql_num_fields
(PHP 4, PHP 5)
mysql_num_fields — Get number of fields in result
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$result
) : intRetrieves the number of fields from a query.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
Return Values
Returns the number of fields in the result set resource on
success or FALSE on failure.
Examples
Example #1 A mysql_num_fields() example
<?php
$result = mysql_query("SELECT id,email FROM people WHERE id = '42'");
if (!$result) {
echo 'Could not run query: ' . mysql_error();
exit;
}
/* returns 2 because id,email === two fields */
echo mysql_num_fields($result);
?>
Notes
Note:
For backward compatibility, the following deprecated alias may be used: mysql_numfields()
See Also
- mysql_select_db() - Select a MySQL database
- mysql_query() - Send a MySQL query
- mysql_fetch_field() - Get column information from a result and return as an object
- mysql_num_rows() - Get number of rows in result
mysql_num_rows
(PHP 4, PHP 5)
mysql_num_rows — Get number of rows in result
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$result
) : intRetrieves the number of rows from a result set. This command is only valid for statements like SELECT or SHOW that return an actual result set. To retrieve the number of rows affected by a INSERT, UPDATE, REPLACE or DELETE query, use mysql_affected_rows().
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
Return Values
The number of rows in a result set on success or FALSE on failure.
Examples
Example #1 mysql_num_rows() example
<?php
$link = mysql_connect("localhost", "mysql_user", "mysql_password");
mysql_select_db("database", $link);
$result = mysql_query("SELECT * FROM table1", $link);
$num_rows = mysql_num_rows($result);
echo "$num_rows Rows\n";
?>
Notes
Note:
If you use mysql_unbuffered_query(), mysql_num_rows() will not return the correct value until all the rows in the result set have been retrieved.
Note:
For backward compatibility, the following deprecated alias may be used: mysql_numrows()
See Also
- mysql_affected_rows() - Get number of affected rows in previous MySQL operation
- mysql_connect() - Open a connection to a MySQL Server
- mysql_data_seek() - Move internal result pointer
- mysql_select_db() - Select a MySQL database
- mysql_query() - Send a MySQL query
mysql_pconnect
(PHP 4, PHP 5)
mysql_pconnect — Open a persistent connection to a MySQL server
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_connect() with
p:host prefix - PDO::__construct() with
PDO::ATTR_PERSISTENTas a driver option
Description
$server = ini_get("mysql.default_host")
[, string $username = ini_get("mysql.default_user")
[, string $password = ini_get("mysql.default_password")
[, int $client_flags = 0
]]]] ) : resourceEstablishes a persistent connection to a MySQL server.
mysql_pconnect() acts very much like mysql_connect() with two major differences.
First, when connecting, the function would first try to find a (persistent) link that's already open with the same host, username and password. If one is found, an identifier for it will be returned instead of opening a new connection.
Second, the connection to the SQL server will not be closed when the execution of the script ends. Instead, the link will remain open for future use (mysql_close() will not close links established by mysql_pconnect()).
This type of link is therefore called 'persistent'.
Parameters
-
server -
The MySQL server. It can also include a port number. e.g. "hostname:port" or a path to a local socket e.g. ":/path/to/socket" for the localhost.
If the PHP directive mysql.default_host is undefined (default), then the default value is 'localhost:3306'
-
username -
The username. Default value is the name of the user that owns the server process.
-
password -
The password. Default value is an empty password.
-
client_flags -
The
client_flagsparameter can be a combination of the following constants: 128 (enableLOAD DATA LOCALhandling),MYSQL_CLIENT_SSL,MYSQL_CLIENT_COMPRESS,MYSQL_CLIENT_IGNORE_SPACEorMYSQL_CLIENT_INTERACTIVE.
Return Values
Returns a MySQL persistent link identifier on success, or FALSE on
failure.
Changelog
| Version | Description |
|---|---|
| 5.5.0 |
This function will generate an E_DEPRECATED
error.
|
Notes
Note:
Note, that these kind of links only work if you are using a module version of PHP. See the Persistent Database Connections section for more information.
Using persistent connections can require a bit of tuning of your Apache and MySQL configurations to ensure that you do not exceed the number of connections allowed by MySQL.
mysql_ping
(PHP 4 >= 4.3.0, PHP 5)
mysql_ping — Ping a server connection or reconnect if there is no connection
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$link_identifier = NULL
] ) : boolChecks whether or not the connection to the server is working. If it has gone down, an automatic reconnection is attempted. This function can be used by scripts that remain idle for a long while, to check whether or not the server has closed the connection and reconnect if necessary.
Note:
Automatic reconnection is disabled by default in versions of MySQL >= 5.0.3.
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns TRUE if the connection to the server MySQL server is working,
otherwise FALSE.
Examples
Example #1 A mysql_ping() example
<?php
set_time_limit(0);
$conn = mysql_connect('localhost', 'mysqluser', 'mypass');
$db = mysql_select_db('mydb');
/* Assuming this query will take a long time */
$result = mysql_query($sql);
if (!$result) {
echo 'Query #1 failed, exiting.';
exit;
}
/* Make sure the connection is still alive, if not, try to reconnect */
if (!mysql_ping($conn)) {
echo 'Lost connection, exiting after query #1';
exit;
}
mysql_free_result($result);
/* So the connection is still alive, let's run another query */
$result2 = mysql_query($sql2);
?>
See Also
- mysql_thread_id() - Return the current thread ID
- mysql_list_processes() - List MySQL processes
mysql_query
(PHP 4, PHP 5)
mysql_query — Send a MySQL query
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
mysql_query() sends a unique query (multiple queries
are not supported) to the currently
active database on the server that's associated with the
specified link_identifier.
Parameters
-
query -
An SQL query
The query string should not end with a semicolon. Data inside the query should be properly escaped.
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
For SELECT, SHOW, DESCRIBE, EXPLAIN and other statements returning resultset,
mysql_query()
returns a resource on success, or FALSE on
error.
For other type of SQL statements, INSERT, UPDATE, DELETE, DROP, etc,
mysql_query() returns TRUE on success
or FALSE on error.
The returned result resource should be passed to mysql_fetch_array(), and other functions for dealing with result tables, to access the returned data.
Use mysql_num_rows() to find out how many rows were returned for a SELECT statement or mysql_affected_rows() to find out how many rows were affected by a DELETE, INSERT, REPLACE, or UPDATE statement.
mysql_query() will also fail and return FALSE
if the user does not have permission to access the table(s) referenced by
the query.
Examples
Example #1 Invalid Query
The following query is syntactically invalid, so
mysql_query() fails and returns FALSE.
<?php
$result = mysql_query('SELECT * WHERE 1=1');
if (!$result) {
die('Invalid query: ' . mysql_error());
}
?>
Example #2 Valid Query
The following query is valid, so mysql_query() returns a resource.
<?php
// This could be supplied by a user, for example
$firstname = 'fred';
$lastname = 'fox';
// Formulate Query
// This is the best way to perform an SQL query
// For more examples, see mysql_real_escape_string()
$query = sprintf("SELECT firstname, lastname, address, age FROM friends
WHERE firstname='%s' AND lastname='%s'",
mysql_real_escape_string($firstname),
mysql_real_escape_string($lastname));
// Perform Query
$result = mysql_query($query);
// Check result
// This shows the actual query sent to MySQL, and the error. Useful for debugging.
if (!$result) {
$message = 'Invalid query: ' . mysql_error() . "\n";
$message .= 'Whole query: ' . $query;
die($message);
}
// Use result
// Attempting to print $result won't allow access to information in the resource
// One of the mysql result functions must be used
// See also mysql_result(), mysql_fetch_array(), mysql_fetch_row(), etc.
while ($row = mysql_fetch_assoc($result)) {
echo $row['firstname'];
echo $row['lastname'];
echo $row['address'];
echo $row['age'];
}
// Free the resources associated with the result set
// This is done automatically at the end of the script
mysql_free_result($result);
?>
See Also
- mysql_connect() - Open a connection to a MySQL Server
- mysql_error() - Returns the text of the error message from previous MySQL operation
- mysql_real_escape_string() - Escapes special characters in a string for use in an SQL statement
- mysql_result() - Get result data
- mysql_fetch_assoc() - Fetch a result row as an associative array
- mysql_unbuffered_query() - Send an SQL query to MySQL without fetching and buffering the result rows
mysql_real_escape_string
(PHP 4 >= 4.3.0, PHP 5)
mysql_real_escape_string — Escapes special characters in a string for use in an SQL statement
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$unescaped_string
[, resource $link_identifier = NULL
] ) : string
Escapes special characters in the unescaped_string,
taking into account the current character set of the connection so that it
is safe to place it in a mysql_query(). If binary data
is to be inserted, this function must be used.
mysql_real_escape_string() calls MySQL's library function
mysql_real_escape_string, which prepends backslashes to the following characters:
\x00, \n,
\r, \, ',
" and \x1a.
This function must always (with few exceptions) be used to make data safe before sending a query to MySQL.
Security: the default character set
The character set must be set either at the server level, or with the API function mysql_set_charset() for it to affect mysql_real_escape_string(). See the concepts section on character sets for more information.
Parameters
-
unescaped_string -
The string that is to be escaped.
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns the escaped string, or FALSE on error.
Errors/Exceptions
Executing this function without a MySQL connection present will
also emit E_WARNING level PHP errors. Only
execute this function with a valid MySQL connection present.
Examples
Example #1 Simple mysql_real_escape_string() example
<?php
// Connect
$link = mysql_connect('mysql_host', 'mysql_user', 'mysql_password')
OR die(mysql_error());
// Query
$query = sprintf("SELECT * FROM users WHERE user='%s' AND password='%s'",
mysql_real_escape_string($user),
mysql_real_escape_string($password));
?>
Example #2 mysql_real_escape_string() requires a connection example
This example demonstrates what happens if a MySQL connection is not present when calling this function.
<?php
// We have not connected to MySQL
$lastname = "O'Reilly";
$_lastname = mysql_real_escape_string($lastname);
$query = "SELECT * FROM actors WHERE last_name = '$_lastname'";
var_dump($_lastname);
var_dump($query);
?>
The above example will output something similar to:
Warning: mysql_real_escape_string(): No such file or directory in /this/test/script.php on line 5 Warning: mysql_real_escape_string(): A link to the server could not be established in /this/test/script.php on line 5 bool(false) string(41) "SELECT * FROM actors WHERE last_name = ''"
Example #3 An example SQL Injection Attack
<?php
// We didn't check $_POST['password'], it could be anything the user wanted! For example:
$_POST['username'] = 'aidan';
$_POST['password'] = "' OR ''='";
// Query database to check if there are any matching users
$query = "SELECT * FROM users WHERE user='{$_POST['username']}' AND password='{$_POST['password']}'";
mysql_query($query);
// This means the query sent to MySQL would be:
echo $query;
?>
The query sent to MySQL:
SELECT * FROM users WHERE user='aidan' AND password='' OR ''=''
This would allow anyone to log in without a valid password.
Notes
Note:
A MySQL connection is required before using mysql_real_escape_string() otherwise an error of level
E_WARNINGis generated, andFALSEis returned. Iflink_identifierisn't defined, the last MySQL connection is used.
Note:
If magic_quotes_gpc is enabled, first apply stripslashes() to the data. Using this function on data which has already been escaped will escape the data twice.
Note:
If this function is not used to escape data, the query is vulnerable to SQL Injection Attacks.
Note: mysql_real_escape_string() does not escape
%and_. These are wildcards in MySQL if combined withLIKE,GRANT, orREVOKE.
See Also
- mysql_set_charset() - Sets the client character set
- mysql_client_encoding() - Returns the name of the character set
- addslashes() - Quote string with slashes
- stripslashes() - Un-quotes a quoted string
- The magic_quotes_gpc directive
- The magic_quotes_runtime directive
mysql_result
(PHP 4, PHP 5)
mysql_result — Get result data
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_data_seek() in conjunction with mysqli_field_seek() and mysqli_fetch_field()
- PDOStatement::fetchColumn()
Description
Retrieves the contents of one cell from a MySQL result set.
When working on large result sets, you should consider using one of the functions that fetch an entire row (specified below). As these functions return the contents of multiple cells in one function call, they're MUCH quicker than mysql_result(). Also, note that specifying a numeric offset for the field argument is much quicker than specifying a fieldname or tablename.fieldname argument.
Parameters
-
result -
The result resource that is being evaluated. This result comes from a call to mysql_query().
-
row -
The row number from the result that's being retrieved. Row numbers start at
0. -
field -
The name or offset of the field being retrieved.
It can be the field's offset, the field's name, or the field's table dot field name (tablename.fieldname). If the column name has been aliased ('select foo as bar from...'), use the alias instead of the column name. If undefined, the first field is retrieved.
Return Values
The contents of one cell from a MySQL result set on success, or
FALSE on failure.
Examples
Example #1 mysql_result() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
if (!mysql_select_db('database_name')) {
die('Could not select database: ' . mysql_error());
}
$result = mysql_query('SELECT name FROM work.employee');
if (!$result) {
die('Could not query:' . mysql_error());
}
echo mysql_result($result, 2); // outputs third employee's name
mysql_close($link);
?>
Notes
Note:
Calls to mysql_result() should not be mixed with calls to other functions that deal with the result set.
See Also
- mysql_fetch_row() - Get a result row as an enumerated array
- mysql_fetch_array() - Fetch a result row as an associative array, a numeric array, or both
- mysql_fetch_assoc() - Fetch a result row as an associative array
- mysql_fetch_object() - Fetch a result row as an object
mysql_select_db
(PHP 4, PHP 5)
mysql_select_db — Select a MySQL database
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_select_db()
- PDO::__construct() (part of dsn)
Description
$database_name
[, resource $link_identifier = NULL
] ) : boolSets the current active database on the server that's associated with the specified link identifier. Every subsequent call to mysql_query() will be made on the active database.
Parameters
-
database_name -
The name of the database that is to be selected.
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 mysql_select_db() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Not connected : ' . mysql_error());
}
// make foo the current db
$db_selected = mysql_select_db('foo', $link);
if (!$db_selected) {
die ('Can\'t use foo : ' . mysql_error());
}
?>
Notes
Note:
For backward compatibility, the following deprecated alias may be used: mysql_selectdb()
See Also
- mysql_connect() - Open a connection to a MySQL Server
- mysql_pconnect() - Open a persistent connection to a MySQL server
- mysql_query() - Send a MySQL query
mysql_set_charset
(PHP 5 >= 5.2.3)
mysql_set_charset — Sets the client character set
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_set_charset()
- PDO: Add
charsetto the connection string, such ascharset=utf8
Description
$charset
[, resource $link_identifier = NULL
] ) : boolSets the default character set for the current connection.
Parameters
-
charset -
A valid character set name.
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns TRUE on success or FALSE on failure.
Notes
Note:
This function requires MySQL 5.0.7 or later.
Note:
This is the preferred way to change the charset. Using mysql_query() to set it (such as
SET NAMES utf8) is not recommended. See the MySQL character set concepts section for more information.
See Also
- Setting character sets in MySQL
- » List of character sets that MySQL supports
- mysql_client_encoding() - Returns the name of the character set
mysql_stat
(PHP 4 >= 4.3.0, PHP 5)
mysql_stat — Get current system status
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$link_identifier = NULL
] ) : stringmysql_stat() returns the current server status.
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
Returns a string with the status for uptime, threads, queries, open tables,
flush tables and queries per second. For a complete list of other status
variables, you have to use the SHOW STATUS SQL command.
If link_identifier is invalid, NULL is returned.
Examples
Example #1 mysql_stat() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$status = explode(' ', mysql_stat($link));
print_r($status);
?>
The above example will output something similar to:
Array
(
[0] => Uptime: 5380
[1] => Threads: 2
[2] => Questions: 1321299
[3] => Slow queries: 0
[4] => Opens: 26
[5] => Flush tables: 1
[6] => Open tables: 17
[7] => Queries per second avg: 245.595
)
Example #2 Alternative mysql_stat() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$result = mysql_query('SHOW STATUS', $link);
while ($row = mysql_fetch_assoc($result)) {
echo $row['Variable_name'] . ' = ' . $row['Value'] . "\n";
}
?>
The above example will output something similar to:
back_log = 50 basedir = /usr/local/ bdb_cache_size = 8388600 bdb_log_buffer_size = 32768 bdb_home = /var/db/mysql/ bdb_max_lock = 10000 bdb_logdir = bdb_shared_data = OFF bdb_tmpdir = /var/tmp/ ...
See Also
- mysql_get_server_info() - Get MySQL server info
- mysql_list_processes() - List MySQL processes
mysql_tablename
(PHP 4, PHP 5)
mysql_tablename — Get table name of field
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- SQL Query:
SHOW TABLES
Description
$result
, int $i
) : string
Retrieves the table name from a result.
This function is deprecated. It is preferable to use
mysql_query() to issue an SQL SHOW TABLES
[FROM db_name] [LIKE 'pattern'] statement instead.
Parameters
-
result -
A result pointer resource that's returned from mysql_list_tables().
-
i -
The integer index (row/table number)
Return Values
The name of the table on success or FALSE on failure.
Use the mysql_tablename() function to traverse this result pointer, or any function for result tables, such as mysql_fetch_array().
Changelog
| Version | Description |
|---|---|
| 5.5.0 |
The mysql_tablename() function is deprecated,
and emits an E_DEPRECATED level error.
|
Examples
Example #1 mysql_tablename() example
<?php
mysql_connect("localhost", "mysql_user", "mysql_password");
$result = mysql_list_tables("mydb");
$num_rows = mysql_num_rows($result);
for ($i = 0; $i < $num_rows; $i++) {
echo "Table: ", mysql_tablename($result, $i), "\n";
}
mysql_free_result($result);
?>
Notes
Note:
The mysql_num_rows() function may be used to determine the number of tables in the result pointer.
See Also
- mysql_list_tables() - List tables in a MySQL database
- mysql_field_table() - Get name of the table the specified field is in
- mysql_db_name() - Retrieves database name from the call to mysql_list_dbs
mysql_thread_id
(PHP 4 >= 4.3.0, PHP 5)
mysql_thread_id — Return the current thread ID
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$link_identifier = NULL
] ) : intRetrieves the current thread ID. If the connection is lost, and a reconnect with mysql_ping() is executed, the thread ID will change. This means only retrieve the thread ID when needed.
Parameters
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
The thread ID on success or FALSE on failure.
Examples
Example #1 mysql_thread_id() example
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
$thread_id = mysql_thread_id($link);
if ($thread_id){
printf("current thread id is %d\n", $thread_id);
}
?>
The above example will output something similar to:
current thread id is 73
See Also
- mysql_ping() - Ping a server connection or reconnect if there is no connection
- mysql_list_processes() - List MySQL processes
mysql_unbuffered_query
(PHP 4 >= 4.0.6, PHP 5)
mysql_unbuffered_query — Send an SQL query to MySQL without fetching and buffering the result rows
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
Description
$query
[, resource $link_identifier = NULL
] ) : resource
mysql_unbuffered_query() sends the SQL query
query to MySQL without automatically
fetching and buffering the result rows as
mysql_query() does. This saves a considerable
amount of memory with SQL queries that produce large result sets,
and you can start working on the result set immediately after the
first row has been retrieved as you don't have to wait until the
complete SQL query has been performed. To use
mysql_unbuffered_query() while multiple database
connections are open, you must specify the optional parameter
link_identifier to identify which connection
you want to use.
Parameters
-
query -
The SQL query to execute.
Data inside the query should be properly escaped.
-
link_identifier -
The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() had been called with no arguments. If no connection is found or established, an
E_WARNINGlevel error is generated.
Return Values
For SELECT, SHOW, DESCRIBE or EXPLAIN statements,
mysql_unbuffered_query()
returns a resource on success, or FALSE on
error.
For other type of SQL statements, UPDATE, DELETE, DROP, etc,
mysql_unbuffered_query() returns TRUE on success
or FALSE on error.
Notes
Note:
The benefits of mysql_unbuffered_query() come at a cost: you cannot use mysql_num_rows() and mysql_data_seek() on a result set returned from mysql_unbuffered_query(), until all rows are fetched. You also have to fetch all result rows from an unbuffered SQL query before you can send a new SQL query to MySQL, using the same
link_identifier.
Table of Contents
- mysql_affected_rows — Get number of affected rows in previous MySQL operation
- mysql_client_encoding — Returns the name of the character set
- mysql_close — Close MySQL connection
- mysql_connect — Open a connection to a MySQL Server
- mysql_create_db — Create a MySQL database
- mysql_data_seek — Move internal result pointer
- mysql_db_name — Retrieves database name from the call to mysql_list_dbs
- mysql_db_query — Selects a database and executes a query on it
- mysql_drop_db — Drop (delete) a MySQL database
- mysql_errno — Returns the numerical value of the error message from previous MySQL operation
- mysql_error — Returns the text of the error message from previous MySQL operation
- mysql_escape_string — Escapes a string for use in a mysql_query
- mysql_fetch_array — Fetch a result row as an associative array, a numeric array, or both
- mysql_fetch_assoc — Fetch a result row as an associative array
- mysql_fetch_field — Get column information from a result and return as an object
- mysql_fetch_lengths — Get the length of each output in a result
- mysql_fetch_object — Fetch a result row as an object
- mysql_fetch_row — Get a result row as an enumerated array
- mysql_field_flags — Get the flags associated with the specified field in a result
- mysql_field_len — Returns the length of the specified field
- mysql_field_name — Get the name of the specified field in a result
- mysql_field_seek — Set result pointer to a specified field offset
- mysql_field_table — Get name of the table the specified field is in
- mysql_field_type — Get the type of the specified field in a result
- mysql_free_result — Free result memory
- mysql_get_client_info — Get MySQL client info
- mysql_get_host_info — Get MySQL host info
- mysql_get_proto_info — Get MySQL protocol info
- mysql_get_server_info — Get MySQL server info
- mysql_info — Get information about the most recent query
- mysql_insert_id — Get the ID generated in the last query
- mysql_list_dbs — List databases available on a MySQL server
- mysql_list_fields — List MySQL table fields
- mysql_list_processes — List MySQL processes
- mysql_list_tables — List tables in a MySQL database
- mysql_num_fields — Get number of fields in result
- mysql_num_rows — Get number of rows in result
- mysql_pconnect — Open a persistent connection to a MySQL server
- mysql_ping — Ping a server connection or reconnect if there is no connection
- mysql_query — Send a MySQL query
- mysql_real_escape_string — Escapes special characters in a string for use in an SQL statement
- mysql_result — Get result data
- mysql_select_db — Select a MySQL database
- mysql_set_charset — Sets the client character set
- mysql_stat — Get current system status
- mysql_tablename — Get table name of field
- mysql_thread_id — Return the current thread ID
- mysql_unbuffered_query — Send an SQL query to MySQL without fetching and buffering the result rows
- Introduction
- Installing/Configuring
- Changelog
- Predefined Constants
- Examples
- MySQL Functions
- mysql_affected_rows — Get number of affected rows in previous MySQL operation
- mysql_client_encoding — Returns the name of the character set
- mysql_close — Close MySQL connection
- mysql_connect — Open a connection to a MySQL Server
- mysql_create_db — Create a MySQL database
- mysql_data_seek — Move internal result pointer
- mysql_db_name — Retrieves database name from the call to mysql_list_dbs
- mysql_db_query — Selects a database and executes a query on it
- mysql_drop_db — Drop (delete) a MySQL database
- mysql_errno — Returns the numerical value of the error message from previous MySQL operation
- mysql_error — Returns the text of the error message from previous MySQL operation
- mysql_escape_string — Escapes a string for use in a mysql_query
- mysql_fetch_array — Fetch a result row as an associative array, a numeric array, or both
- mysql_fetch_assoc — Fetch a result row as an associative array
- mysql_fetch_field — Get column information from a result and return as an object
- mysql_fetch_lengths — Get the length of each output in a result
- mysql_fetch_object — Fetch a result row as an object
- mysql_fetch_row — Get a result row as an enumerated array
- mysql_field_flags — Get the flags associated with the specified field in a result
- mysql_field_len — Returns the length of the specified field
- mysql_field_name — Get the name of the specified field in a result
- mysql_field_seek — Set result pointer to a specified field offset
- mysql_field_table — Get name of the table the specified field is in
- mysql_field_type — Get the type of the specified field in a result
- mysql_free_result — Free result memory
- mysql_get_client_info — Get MySQL client info
- mysql_get_host_info — Get MySQL host info
- mysql_get_proto_info — Get MySQL protocol info
- mysql_get_server_info — Get MySQL server info
- mysql_info — Get information about the most recent query
- mysql_insert_id — Get the ID generated in the last query
- mysql_list_dbs — List databases available on a MySQL server
- mysql_list_fields — List MySQL table fields
- mysql_list_processes — List MySQL processes
- mysql_list_tables — List tables in a MySQL database
- mysql_num_fields — Get number of fields in result
- mysql_num_rows — Get number of rows in result
- mysql_pconnect — Open a persistent connection to a MySQL server
- mysql_ping — Ping a server connection or reconnect if there is no connection
- mysql_query — Send a MySQL query
- mysql_real_escape_string — Escapes special characters in a string for use in an SQL statement
- mysql_result — Get result data
- mysql_select_db — Select a MySQL database
- mysql_set_charset — Sets the client character set
- mysql_stat — Get current system status
- mysql_tablename — Get table name of field
- mysql_thread_id — Return the current thread ID
- mysql_unbuffered_query — Send an SQL query to MySQL without fetching and buffering the result rows
MySQL Native Driver
Introduction
MySQL Native Driver is a replacement for the MySQL Client Library (libmysqlclient). MySQL Native Driver is part of the official PHP sources as of PHP 5.3.0.
The MySQL database extensions MySQL extension,
mysqli and PDO MYSQL all communicate with the MySQL
server. In the past, this was done by the extension using the services
provided by the MySQL Client Library. The extensions were compiled
against the MySQL Client Library in order to use its client-server
protocol.
With MySQL Native Driver there is now an alternative, as the MySQL database extensions can be compiled to use MySQL Native Driver instead of the MySQL Client Library.
MySQL Native Driver is written in C as a PHP extension.
Overview
What it is not
Although MySQL Native Driver is written as a PHP extension, it is
important to note that it does not provide a new API to the PHP
programmer. The programmer APIs for MySQL database connectivity are
provided by the MySQL extension, mysqli and PDO
MYSQL. These extensions can now use the services of MySQL Native
Driver to communicate with the MySQL Server. Therefore, you should not
think of MySQL Native Driver as an API.
Why use it?
Using the MySQL Native Driver offers a number of advantages over using the MySQL Client Library.
The older MySQL Client Library was written by MySQL AB (now Oracle Corporation) and so was released under the MySQL license. This ultimately led to MySQL support being disabled by default in PHP. However, the MySQL Native Driver has been developed as part of the PHP project, and is therefore released under the PHP license. This removes licensing issues that have been problematic in the past.
Also, in the past, you needed to build the MySQL database extensions against a copy of the MySQL Client Library. This typically meant you needed to have MySQL installed on a machine where you were building the PHP source code. Also, when your PHP application was running, the MySQL database extensions would call down to the MySQL Client library file at run time, so the file needed to be installed on your system. With MySQL Native Driver that is no longer the case as it is included as part of the standard distribution. So you do not need MySQL installed in order to build PHP or run PHP database applications.
Because MySQL Native Driver is written as a PHP extension, it is tightly coupled to the workings of PHP. This leads to gains in efficiency, especially when it comes to memory usage, as the driver uses the PHP memory management system. It also supports the PHP memory limit. Using MySQL Native Driver leads to comparable or better performance than using MySQL Client Library, it always ensures the most efficient use of memory. One example of the memory efficiency is the fact that when using the MySQL Client Library, each row is stored in memory twice, whereas with the MySQL Native Driver each row is only stored once in memory.
Note: Reporting memory usage
Because MySQL Native Driver uses the PHP memory management system, its memory usage can be tracked with memory_get_usage(). This is not possible with libmysqlclient because it uses the C function malloc() instead.
Special features
MySQL Native Driver also provides some special features not available when the MySQL database extensions use MySQL Client Library. These special features are listed below:
-
Improved persistent connections
-
The special function mysqli_fetch_all()
-
Performance statistics calls: mysqli_get_cache_stats(), mysqli_get_client_stats(), mysqli_get_connection_stats()
The performance statistics facility can prove to be very useful in identifying performance bottlenecks.
MySQL Native Driver also allows for persistent connections when used
with the mysqli extension.
SSL Support
MySQL Native Driver has supported SSL since PHP version 5.3.3
Compressed Protocol Support
As of PHP 5.3.2 MySQL Native Driver supports the compressed client
server protocol. MySQL Native Driver did not support this in 5.3.0 and
5.3.1. Extensions such as ext/mysql,
ext/mysqli, that are configured to use MySQL Native Driver,
can also take advantage of this feature. Note that PDO_MYSQL
does NOT support compression when used together with mysqlnd.
Named Pipes Support
Named pipes support for Windows was added in PHP version 5.4.0.
Installation
Changelog
| Version | Description |
|---|---|
| 5.3.0 |
The MySQL Native Driver was added, with support for all MySQL
extensions (i.e., mysql, mysqli and PDO_MYSQL). Passing in
mysqlnd to the appropriate configure switch
enables this support.
|
| 5.4.0 |
The MySQL Native Driver is now the default for all MySQL
extensions (i.e., mysql, mysqli and PDO_MYSQL). Passing
in mysqlnd to configure is now optional.
|
| 5.5.0 | SHA-256 Authentication Plugin support was added |
Installation on Unix
The MySQL database extensions must be configured to use the MySQL Client Library. In order to use the MySQL Native Driver, PHP needs to be built specifying that the MySQL database extensions are compiled with MySQL Native Driver support. This is done through configuration options prior to building the PHP source code.
For example, to build the MySQL extension, mysqli
and PDO MYSQL using the MySQL Native Driver, the following command
would be given:
./configure --with-mysql=mysqlnd \ --with-mysqli=mysqlnd \ --with-pdo-mysql=mysqlnd \ [other options]
Installation on Windows
In the official PHP Windows distributions from 5.3 onwards, MySQL Native Driver is enabled by default, so no additional configuration is required to use it. All MySQL database extensions will use MySQL Native Driver in this case.
SHA-256 Authentication Plugin support
The MySQL Native Driver requires the OpenSSL functionality of PHP to be loaded and enabled to connect to MySQL through accounts that use the MySQL SHA-256 Authentication Plugin. For example, PHP could be configured using:
./configure --with-mysql=mysqlnd \ --with-mysqli=mysqlnd \ --with-pdo-mysql=mysqlnd \ --with-openssl [other options]
Runtime Configuration
The behaviour of these functions is affected by settings in php.ini.
| Name | Default | Changeable | Changelog |
|---|---|---|---|
| mysqlnd.collect_statistics | "1" | PHP_INI_SYSTEM | Available since PHP 5.3.0. |
| mysqlnd.collect_memory_statistics | "0" | PHP_INI_SYSTEM | Available since PHP 5.3.0. |
| mysqlnd.debug | "" | PHP_INI_SYSTEM | Available since PHP 5.3.0. |
| mysqlnd.log_mask | 0 | PHP_INI_ALL | Available since PHP 5.3.0 |
| mysqlnd.mempool_default_size | 16000 | PHP_INI_ALL | Available since PHP 5.3.3 |
| mysqlnd.net_read_timeout | "86400" | PHP_INI_ALL |
Available since PHP 5.3.0. Before PHP 7.2.0 the default value was "31536000"
and the changeability was PHP_INI_SYSTEM
|
| mysqlnd.net_cmd_buffer_size | 5.3.0 - "2048", 5.3.1 - "4096" | PHP_INI_SYSTEM | Available since PHP 5.3.0. |
| mysqlnd.net_read_buffer_size | "32768" | PHP_INI_SYSTEM | Available since PHP 5.3.0. |
| mysqlnd.sha256_server_public_key | "" | PHP_INI_PERDIR | Available since PHP 5.5.0. |
| mysqlnd.trace_alloc | "" | PHP_INI_SYSTEM | Available since PHP 5.5.0. |
| mysqlnd.fetch_data_copy | 0 | PHP_INI_ALL | Available since PHP 5.6.0. |
Here's a short explanation of the configuration directives.
-
mysqlnd.collect_statisticsboolean -
Enables the collection of various client statistics which can be accessed through mysqli_get_client_stats(), mysqli_get_connection_stats(), mysqli_get_cache_stats() and are shown in
mysqlndsection of the output of the phpinfo() function as well.This configuration setting enables all MySQL Native Driver statistics except those relating to memory management.
-
mysqlnd.collect_memory_statisticsboolean -
Enable the collection of various memory statistics which can be accessed through mysqli_get_client_stats(), mysqli_get_connection_stats(), mysqli_get_cache_stats() and are shown in
mysqlndsection of the output of the phpinfo() function as well.This configuration setting enables the memory management statistics within the overall set of MySQL Native Driver statistics.
-
mysqlnd.debugstring -
Records communication from all extensions using
mysqlndto the specified log file.The format of the directive is
mysqlnd.debug = "option1[,parameter_option1][:option2[,parameter_option2]]".The options for the format string are as follows:
-
A[,file] - Appends trace output to specified file. Also ensures that data is written after each write. This is done by closing and reopening the trace file (this is slow). It helps ensure a complete log file should the application crash.
-
a[,file] - Appends trace output to the specified file.
-
d - Enables output from DBUG_<N> macros for the current state. May be followed by a list of keywords which selects output only for the DBUG macros with that keyword. An empty list of keywords implies output for all macros.
-
f[,functions] - Limits debugger actions to the specified list of functions. An empty list of functions implies that all functions are selected.
-
F - Marks each debugger output line with the name of the source file containing the macro causing the output.
-
i - Marks each debugger output line with the PID of the current process.
-
L - Marks each debugger output line with the name of the source file line number of the macro causing the output.
-
n - Marks each debugger output line with the current function nesting depth
-
o[,file] - Similar to a[,file] but overwrites old file, and does not append.
-
O[,file] - Similar to A[,file] but overwrites old file, and does not append.
-
t[,N] - Enables function control flow tracing. The maximum nesting depth is specified by N, and defaults to 200.
-
x - This option activates profiling.
-
m - Trace memory allocation and deallocation related calls.
Example:
d:t:x:O,/tmp/mysqlnd.trace
Note:
This feature is only available with a debug build of PHP. Works on Microsoft Windows if using a debug build of PHP and PHP was built using Microsoft Visual C version 9 and above.
-
-
mysqlnd.log_maskinteger -
Defines which queries will be logged. The default 0, which disables logging. Define using an integer, and not with PHP constants. For example, a value of 48 (16 + 32) will log slow queries which either use 'no good index' (SERVER_QUERY_NO_GOOD_INDEX_USED = 16) or no index at all (SERVER_QUERY_NO_INDEX_USED = 32). A value of 2043 (1 + 2 + 8 + ... + 1024) will log all slow query types.
The types are as follows: SERVER_STATUS_IN_TRANS=1, SERVER_STATUS_AUTOCOMMIT=2, SERVER_MORE_RESULTS_EXISTS=8, SERVER_QUERY_NO_GOOD_INDEX_USED=16, SERVER_QUERY_NO_INDEX_USED=32, SERVER_STATUS_CURSOR_EXISTS=64, SERVER_STATUS_LAST_ROW_SENT=128, SERVER_STATUS_DB_DROPPED=256, SERVER_STATUS_NO_BACKSLASH_ESCAPES=512, and SERVER_QUERY_WAS_SLOW=1024.
-
mysqlnd.mempool_default_sizeinteger -
Default size of the mysqlnd memory pool, which is used by result sets.
-
mysqlnd.net_read_timeoutinteger -
mysqlndand the MySQL Client Library,libmysqlclientuse different networking APIs.mysqlnduses PHP streams, whereaslibmysqlclientuses its own wrapper around the operating level network calls. PHP, by default, sets a read timeout of 60s for streams. This is set via php.ini,default_socket_timeout. This default applies to all streams that set no other timeout value.mysqlnddoes not set any other value and therefore connections of long running queries can be disconnected afterdefault_socket_timeoutseconds resulting in an error message2006 - MySQL Server has gone away
. The MySQL Client Library sets a default timeout of 24 * 3600 seconds (1 day) and waits for other timeouts to occur, such as TCP/IP timeouts.mysqlndnow uses the same very long timeout. The value is configurable through a new php.ini setting:mysqlnd.net_read_timeout.mysqlnd.net_read_timeoutgets used by any extension (ext/mysql,ext/mysqli,PDO_MySQL) that usesmysqlnd.mysqlndtells PHP Streams to usemysqlnd.net_read_timeout. Please note that there may be subtle differences betweenMYSQL_OPT_READ_TIMEOUTfrom the MySQL Client Library and PHP Streams, for exampleMYSQL_OPT_READ_TIMEOUTis documented to work only for TCP/IP connections and, prior to MySQL 5.1.2, only for Windows. PHP streams may not have this limitation. Please check the streams documentation, if in doubt. -
mysqlnd.net_cmd_buffer_sizeinteger -
mysqlndallocates an internal command/network buffer ofmysqlnd.net_cmd_buffer_size(in php.ini) bytes for every connection. If a MySQL Client Server protocol command, for example,COM_QUERY(normal
query), does not fit into the buffer,mysqlndwill grow the buffer to the size required for sending the command. Whenever the buffer gets extended for one connection,command_buffer_too_smallwill be incremented by one.If
mysqlndhas to grow the buffer beyond its initial size ofmysqlnd.net_cmd_buffer_sizebytes for almost every connection, you should consider increasing the default size to avoid re-allocations.The default buffer size is 2048 bytes in PHP 5.3.0. In later versions the default is 4096 bytes.
It is recommended that the buffer size be set to no less than 4096 bytes because
mysqlndalso uses it when reading certain communication packet from MySQL. In PHP 5.3.0,mysqlndwill not grow the buffer if MySQL sends a packet that is larger than the current size of the buffer. As a consequence,mysqlndis unable to decode the packet and the client application will get an error. There are only two situations when the packet can be larger than the 2048 bytes default ofmysqlnd.net_cmd_buffer_sizein PHP 5.3.0: the packet transports a very long error message, or the packet holds column meta data fromCOM_LIST_FIELD(mysql_list_fields()and the meta data come from a string column with a very long default value (>1900 bytes).As of PHP 5.3.2 mysqlnd does not allow setting buffers smaller than 4096 bytes.
The value can also be set using
mysqli_options(link, MYSQLI_OPT_NET_CMD_BUFFER_SIZE, size). -
mysqlnd.net_read_buffer_sizeinteger -
Maximum read chunk size in bytes when reading the body of a MySQL command packet. The MySQL client server protocol encapsulates all its commands in packets. The packets consist of a small header and a body with the actual payload. The size of the body is encoded in the header.
mysqlndreads the body in chunks ofMIN(header.size, mysqlnd.net_read_buffer_size)bytes. If a packet body is larger thanmysqlnd.net_read_buffer_sizebytes,mysqlndhas to callread()multiple times.The value can also be set using
mysqli_options(link, MYSQLI_OPT_NET_READ_BUFFER_SIZE, size). -
mysqlnd.sha256_server_public_keystring -
SHA-256 Authentication Plugin related. File with the MySQL server public RSA key.
Clients can either omit setting a public RSA key, specify the key through this PHP configuration setting or set the key at runtime using mysqli_options(). If not public RSA key file is given by the client, then the key will be exchanged as part of the standard SHA-256 Authentication Plugin authentication procedure.
-
mysqlnd.trace_allocstring -
-
mysqlnd.fetch_data_copyinteger -
Enforce copying result sets from the internal result set buffers into PHP variables instead of using the default reference and copy-on-write logic. Please, see the memory management implementation notes for further details.
Copying result sets instead of having PHP variables reference them allows releasing the memory occupied for the PHP variables earlier. Depending on the user API code, the actual database quries and the size of their result sets this may reduce the memory footprint of mysqlnd.
Do not set if using PDO_MySQL. PDO_MySQL has not yet been updated to support the new fetch mode.
Incompatibilities
MySQL Native Driver is in most cases compatible with MySQL Client Library
(libmysql). This section documents incompatibilities
between these libraries.
-
Values of
bitdata type are returned as binary strings (e.g. "\0" or "\x1F") withlibmysqland as decimal strings (e.g. "0" or "31") withmysqlnd. If you want the code to be compatible with both libraries then always return bit fields as numbers from MySQL with a query like this:SELECT bit + 0 FROM table.
Persistent Connections
Using Persistent Connections
If mysqli is used with mysqlnd,
when a persistent connection is created it generates a
COM_CHANGE_USER
(mysql_change_user()) call on the server. This
ensures that re-authentication of the connection takes place.
As there is some overhead associated with the
COM_CHANGE_USER call, it is possible to switch this
off at compile time. Reusing a persistent connection will then
generate a COM_PING (mysql_ping)
call to simply test the connection is reusable.
Generation of COM_CHANGE_USER can be switched off
with the compile flag
MYSQLI_NO_CHANGE_USER_ON_PCONNECT. For example:
shell# CFLAGS="-DMYSQLI_NO_CHANGE_USER_ON_PCONNECT" ./configure --with-mysql=/usr/local/mysql/ --with-mysqli=/usr/local/mysql/bin/mysql_config --with-pdo-mysql=/usr/local/mysql/bin/mysql_config --enable-debug && make clean && make -j6
Or alternatively:
shell# export CFLAGS="-DMYSQLI_NO_CHANGE_USER_ON_PCONNECT" shell# configure --whatever-option shell# make clean shell# make
Note that only mysqli on mysqlnd
uses COM_CHANGE_USER. Other extension-driver
combinations use COM_PING on initial use of a
persistent connection.
Statistics
Using Statistical Data
MySQL Native Driver contains support for gathering statistics on the communication between the client and the server. The statistics gathered are of two main types:
-
Client statistics
-
Connection statistics
If you are using the mysqli extension, these
statistics can be obtained through two API calls:
Note:
Statistics are aggregated among all extensions that use MySQL Native Driver. For example, when compiling both
ext/mysqlandext/mysqliagainst MySQL Native Driver, both function calls ofext/mysqlandext/mysqliwill change the statistics. There is no way to find out how much a certain API call of any extension that has been compiled against MySQL Native Driver has impacted a certain statistic. You can configure the PDO MySQL Driver,ext/mysqlandext/mysqlito optionally use the MySQL Native Driver. When doing so, all three extensions will change the statistics.
Accessing Client Statistics
To access client statistics, you need to call mysqli_get_client_stats(). The function call does not require any parameters.
The function returns an associative array that contains the name of the statistic as the key and the statistical data as the value.
Client statistics can also be accessed by calling the phpinfo() function.
Accessing Connection Statistics
To access connection statistics call mysqli_get_connection_stats(). This takes the database connection handle as the parameter.
The function returns an associative array that contains the name of the statistic as the key and the statistical data as the value.
Buffered and Unbuffered Result Sets
Result sets can be buffered or unbuffered. Using default settings,
ext/mysql and ext/mysqli work
with buffered result sets for normal (non prepared statement) queries.
Buffered result sets are cached on the client. After the query
execution all results are fetched from the MySQL Server and stored in
a cache on the client. The big advantage of buffered result sets is
that they allow the server to free all resources allocated to a result
set, once the results have been fetched by the client.
Unbuffered result sets on the other hand are kept much longer on the
server. If you want to reduce memory consumption on the client, but
increase load on the server, use unbuffered results. If you experience
a high server load and the figures for unbuffered result sets are
high, you should consider moving the load to the clients. Clients
typically scale better than servers. Load
does not only
refer to memory buffers - the server also needs to keep other
resources open, for example file handles and threads, before a result
set can be freed.
Prepared Statements use unbuffered result sets by default. However, you can use mysqli_stmt_store_result() to enable buffered result sets.
Statistics returned by MySQL Native Driver
The following tables show a list of statistics returned by the mysqli_get_client_stats() and mysqli_get_connection_stats() functions.
| Statistic | Scope | Description | Notes |
|---|---|---|---|
bytes_sent |
Connection | Number of bytes sent from PHP to the MySQL server | Can be used to check the efficiency of the compression protocol |
bytes_received |
Connection | Number of bytes received from MySQL server | Can be used to check the efficiency of the compression protocol |
packets_sent |
Connection | Number of MySQL Client Server protocol packets sent | Used for debugging Client Server protocol implementation |
packets_received |
Connection | Number of MySQL Client Server protocol packets received | Used for debugging Client Server protocol implementation |
protocol_overhead_in |
Connection | MySQL Client Server protocol overhead in bytes for incoming traffic. Currently only the Packet Header (4 bytes) is considered as overhead. protocol_overhead_in = packets_received * 4 | Used for debugging Client Server protocol implementation |
protocol_overhead_out |
Connection | MySQL Client Server protocol overhead in bytes for outgoing traffic. Currently only the Packet Header (4 bytes) is considered as overhead. protocol_overhead_out = packets_sent * 4 | Used for debugging Client Server protocol implementation |
bytes_received_ok_packet |
Connection | Total size of bytes of MySQL Client Server protocol OK packets received. OK packets can contain a status message. The length of the status message can vary and thus the size of an OK packet is not fixed. | Used for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
packets_received_ok |
Connection | Number of MySQL Client Server protocol OK packets received. | Used for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
bytes_received_eof_packet |
Connection | Total size in bytes of MySQL Client Server protocol EOF packets received. EOF can vary in size depending on the server version. Also, EOF can transport an error message. | Used for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
packets_received_eof |
Connection | Number of MySQL Client Server protocol EOF packets. Like with other packet statistics the number of packets will be increased even if PHP does not receive the expected packet but, for example, an error message. | Used for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
bytes_received_rset_header_packet |
Connection | Total size in bytes of MySQL Client Server protocol result set header
packets. The size of the packets varies depending on the payload
(LOAD LOCAL INFILE, INSERT,
UPDATE, SELECT, error
message). |
Used for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
packets_received_rset_header |
Connection | Number of MySQL Client Server protocol result set header packets. | Used for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
bytes_received_rset_field_meta_packet |
Connection | Total size in bytes of MySQL Client Server protocol result set meta data (field information) packets. Of course the size varies with the fields in the result set. The packet may also transport an error or an EOF packet in case of COM_LIST_FIELDS. | Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
packets_received_rset_field_meta |
Connection | Number of MySQL Client Server protocol result set meta data (field information) packets. | Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
bytes_received_rset_row_packet |
Connection | Total size in bytes of MySQL Client Server protocol result set row data
packets. The packet may also transport an error or an EOF packet.
You can reverse engineer the number of error and EOF packets by
subtracting rows_fetched_from_server_normal
and rows_fetched_from_server_ps from
bytes_received_rset_row_packet. |
Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
packets_received_rset_row |
Connection | Number of MySQL Client Server protocol result set row data packets and their total size in bytes. | Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
bytes_received_prepare_response_packet |
Connection | Total size in bytes of MySQL Client Server protocol OK for Prepared
Statement Initialization packets (prepared statement init
packets). The packet may also transport an error. The packet size
depends on the MySQL version: 9 bytes with MySQL 4.1 and 12 bytes
from MySQL 5.0 on. There is no safe way to know how many errors
happened. You may be able to guess that an error has occurred if,
for example, you always connect to MySQL 5.0 or newer and,
bytes_received_prepare_response_packet !=
packets_received_prepare_response * 12. See
also ps_prepared_never_executed,
ps_prepared_once_executed. |
Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
packets_received_prepare_response |
Connection | Number of MySQL Client Server protocol OK for Prepared Statement Initialization packets (prepared statement init packets). | Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
bytes_received_change_user_packet |
Connection | Total size in bytes of MySQL Client Server protocol COM_CHANGE_USER packets. The packet may also transport an error or EOF. | Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
packets_received_change_user |
Connection | Number of MySQL Client Server protocol COM_CHANGE_USER packets | Only useful for debugging CS protocol implementation. Note that the total size in bytes includes the size of the header packet (4 bytes, see protocol overhead). |
packets_sent_command |
Connection | Number of MySQL Client Server protocol commands sent from PHP to MySQL. There is no way to know which specific commands and how many of them have been sent. At its best you can use it to check if PHP has sent any commands to MySQL to know if you can consider to disable MySQL support in your PHP binary. There is also no way to reverse engineer the number of errors that may have occurred while sending data to MySQL. The only error that is recorded is command_buffer_too_small (see below). | Only useful for debugging CS protocol implementation. |
bytes_received_real_data_normal |
Connection | Number of bytes of payload fetched by the PHP client from
mysqlnd using the text protocol. |
This is the size of the actual data contained in result sets that do not
originate from prepared statements and which have been fetched by
the PHP client. Note that although a full result set may have been
pulled from MySQL by mysqlnd, this statistic
only counts actual data pulled from mysqlnd by
the PHP client. An example of a code sequence that will increase
the value is as follows:
$mysqli = new mysqli();
$res = $mysqli->query("SELECT 'abc'");
$res->fetch_assoc();
$res->close();
Every fetch operation will increase the value. The statistic will not be increased if the result set is only buffered on the client, but not fetched, such as in the following example:
$mysqli = new mysqli();
$res = $mysqli->query("SELECT 'abc'");
$res->close();
This statistic is available as of PHP version 5.3.4. |
bytes_received_real_data_ps |
Connection | Number of bytes of the payload fetched by the PHP client from
mysqlnd using the prepared statement protocol. |
This is the size of the actual data contained in result sets that
originate from prepared statements and which has been fetched by
the PHP client. The value will not be increased if the result set
is not subsequently read by the PHP client. Note that although a
full result set may have been pulled from MySQL by
mysqlnd, this statistic only counts actual data
pulled from mysqlnd by the PHP client. See also
bytes_received_real_data_normal. This statistic
is available as of PHP version 5.3.4. |
Result Set
| Statistic | Scope | Description | Notes |
|---|---|---|---|
result_set_queries |
Connection | Number of queries that have generated a result set. Examples of queries
that generate a result set: SELECT,
SHOW. The statistic will not be incremented if
there is an error reading the result set header packet from the
line. |
You may use it as an indirect measure for the number of queries PHP has sent to MySQL, for example, to identify a client that causes a high database load. |
non_result_set_queries |
Connection | Number of queries that did not generate a result set. Examples of
queries that do not generate a result set:
INSERT, UPDATE,
LOAD DATA. The
statistic will not be incremented if there is an error reading the
result set header packet from the line. |
You may use it as an indirect measure for the number of queries PHP has sent to MySQL, for example, to identify a client that causes a high database load. |
no_index_used |
Connection | Number of queries that have generated a result set but did not use an index (see also mysqld start option –log-queries-not-using-indexes). If you want these queries to be reported you can use mysqli_report(MYSQLI_REPORT_INDEX) to make ext/mysqli throw an exception. If you prefer a warning instead of an exception use mysqli_report(MYSQLI_REPORT_INDEX ^ MYSQLI_REPORT_STRICT). | |
bad_index_used |
Connection | Number of queries that have generated a result set and did not use a good index (see also mysqld start option –log-slow-queries). | If you want these queries to be reported you can use mysqli_report(MYSQLI_REPORT_INDEX) to make ext/mysqli throw an exception. If you prefer a warning instead of an exception use mysqli_report(MYSQLI_REPORT_INDEX ^ MYSQLI_REPORT_STRICT) |
slow_queries |
Connection | SQL statements that took more than long_query_time
seconds to execute and required at least
min_examined_row_limit rows to be examined. |
Not reported through mysqli_report() |
buffered_sets |
Connection | Number of buffered result sets returned by normalqueries. Normalmeans not prepared statementin the following notes. |
Examples of API calls that will buffer result sets on the client: mysql_query(), mysqli_query(), mysqli_store_result(), mysqli_stmt_get_result(). Buffering result sets on the client ensures that server resources are freed as soon as possible and it makes result set scrolling easier. The downside is the additional memory consumption on the client for buffering data. Note that mysqlnd (unlike the MySQL Client Library) respects the PHP memory limit because it uses PHP internal memory management functions to allocate memory. This is also the reason why memory_get_usage() reports a higher memory consumption when using mysqlnd instead of the MySQL Client Library. memory_get_usage() does not measure the memory consumption of the MySQL Client Library at all because the MySQL Client Library does not use PHP internal memory management functions monitored by the function! |
unbuffered_sets |
Connection | Number of unbuffered result sets returned by normal (non prepared statement) queries. | Examples of API calls that will not buffer result sets on the client: mysqli_use_result() |
ps_buffered_sets |
Connection | Number of buffered result sets returned by prepared statements. By default prepared statements are unbuffered. | Examples of API calls that will buffer result sets on the client:
mysqli_stmt_store_result |
ps_unbuffered_sets |
Connection | Number of unbuffered result sets returned by prepared statements. | By default prepared statements are unbuffered. |
flushed_normal_sets |
Connection | Number of result sets from normal (non prepared statement) queries with unread data which have been flushed silently for you. Flushing happens only with unbuffered result sets. | Unbuffered result sets must be fetched completely before a new query can
be run on the connection otherwise MySQL will throw an error. If
the application does not fetch all rows from an unbuffered result
set, mysqlnd does implicitly fetch the result set to clear the
line. See also rows_skipped_normal,
rows_skipped_ps. Some possible causes for an
implicit flush:
|
flushed_ps_sets |
Connection | Number of result sets from prepared statements with unread data which have been flushed silently for you. Flushing happens only with unbuffered result sets. | Unbuffered result sets must be fetched completely before a new query can
be run on the connection otherwise MySQL will throw an error. If
the application does not fetch all rows from an unbuffered result
set, mysqlnd does implicitly fetch the result set to clear the
line. See also rows_skipped_normal,
rows_skipped_ps. Some possible causes for an
implicit flush:
|
ps_prepared_never_executed |
Connection | Number of statements prepared but never executed. | Prepared statements occupy server resources. You should not prepare a statement if you do not plan to execute it. |
ps_prepared_once_executed |
Connection | Number of prepared statements executed only one. | One of the ideas behind prepared statements is that the same query gets
executed over and over again (with different parameters) and some
parsing and other preparation work can be saved, if statement
execution is split up in separate prepare and execute stages. The
idea is to prepare once and cacheresults, for example, the parse tree to be reused during multiple statement executions. If you execute a prepared statement only once the two stage processing can be inefficient compared to normalqueries because all the caching means extra work and it takes (limited) server resources to hold the cached information. Consequently, prepared statements that are executed only once may cause performance hurts. |
rows_fetched_from_server_normal,
rows_fetched_from_server_ps |
Connection | Total number of result set rows successfully fetched from MySQL regardless if the client application has consumed them or not. Some of the rows may not have been fetched by the client application but have been flushed implicitly. | See also packets_received_rset_row |
rows_buffered_from_client_normal,
rows_buffered_from_client_ps |
Connection | Total number of successfully buffered rows originating from a "normal" query or a prepared statement. This is the number of rows that have been fetched from MySQL and buffered on client. Note that there are two distinct statistics on rows that have been buffered (MySQL to mysqlnd internal buffer) and buffered rows that have been fetched by the client application (mysqlnd internal buffer to client application). If the number of buffered rows is higher than the number of fetched buffered rows it can mean that the client application runs queries that cause larger result sets than needed resulting in rows not read by the client. | Examples of queries that will buffer results: mysqli_query(), mysqli_store_result() |
rows_fetched_from_client_normal_buffered,
rows_fetched_from_client_ps_buffered |
Connection | Total number of rows fetched by the client from a buffered result set created by a normal query or a prepared statement. | |
rows_fetched_from_client_normal_unbuffered,
rows_fetched_from_client_ps_unbuffered |
Connection | Total number of rows fetched by the client from a unbuffered result set created by a "normal" query or a prepared statement. | |
rows_fetched_from_client_ps_cursor |
Connection | Total number of rows fetch by the client from a cursor created by a prepared statement. | |
rows_skipped_normal,
rows_skipped_ps |
Connection | Reserved for future use (currently not supported) | |
copy_on_write_saved,
copy_on_write_performed |
Process | With mysqlnd, variables returned by the extensions point into mysqlnd internal network result buffers. If you do not change the variables, fetched data will be kept only once in memory. If you change the variables, mysqlnd has to perform a copy-on-write to protect the internal network result buffers from being changed. With the MySQL Client Library you always hold fetched data twice in memory. Once in the internal MySQL Client Library buffers and once in the variables returned by the extensions. In theory mysqlnd can save up to 40% memory. However, note that the memory saving cannot be measured using memory_get_usage(). | |
explicit_free_result,
implicit_free_result |
Connection, Process (only during prepared statement cleanup) | Total number of freed result sets. | The free is always considered explicit but for result sets created by an
init command, for example,
mysqli_options(MYSQLI_INIT_COMMAND , ...) |
proto_text_fetched_null,
proto_text_fetched_bit,
proto_text_fetched_tinyint
proto_text_fetched_short,
proto_text_fetched_int24,
proto_text_fetched_int
proto_text_fetched_bigint,
proto_text_fetched_decimal,
proto_text_fetched_float
proto_text_fetched_double,
proto_text_fetched_date,
proto_text_fetched_year
proto_text_fetched_time,
proto_text_fetched_datetime,
proto_text_fetched_timestamp
proto_text_fetched_string,
proto_text_fetched_blob,
proto_text_fetched_enum
proto_text_fetched_set,
proto_text_fetched_geometry,
proto_text_fetched_other |
Connection | Total number of columns of a certain type fetched from a normal query (MySQL text protocol). | Mapping from C API / MySQL meta data type to statistics name:
Note that the MYSQL_*-type constants may not be associated with the very same SQL column types in every version of MySQL. |
proto_binary_fetched_null,
proto_binary_fetched_bit,
proto_binary_fetched_tinyint
proto_binary_fetched_short,
proto_binary_fetched_int24,
proto_binary_fetched_int,
proto_binary_fetched_bigint,
proto_binary_fetched_decimal,
proto_binary_fetched_float,
proto_binary_fetched_double,
proto_binary_fetched_date,
proto_binary_fetched_year,
proto_binary_fetched_time,
proto_binary_fetched_datetime,
proto_binary_fetched_timestamp,
proto_binary_fetched_string,
proto_binary_fetched_blob,
proto_binary_fetched_enum,
proto_binary_fetched_set,
proto_binary_fetched_geometry,
proto_binary_fetched_other |
Connection | Total number of columns of a certain type fetched from a prepared statement (MySQL binary protocol). | For type mapping see proto_text_* described in the
preceding text. |
| Statistic | Scope | Description | Notes |
|---|---|---|---|
connect_success, connect_failure |
Connection | Total number of successful / failed connection attempt. | Reused connections and all other kinds of connections are included. |
reconnect |
Process | Total number of (real_)connect attempts made on an already opened connection handle. | The code sequence $link = new mysqli(...);
$link->real_connect(...) will cause a reconnect. But
$link = new mysqli(...); $link->connect(...)
will not because $link->connect(...) will
explicitly close the existing connection before a new connection
is established. |
pconnect_success |
Connection | Total number of successful persistent connection attempts. | Note that connect_success holds the sum of successful
persistent and non-persistent connection attempts. The number of
successful non-persistent connection attempts is
connect_success -
pconnect_success. |
active_connections |
Connection | Total number of active persistent and non-persistent connections. | |
active_persistent_connections |
Connection | Total number of active persistent connections. | The total number of active non-persistent connections is
active_connections -
active_persistent_connections. |
explicit_close |
Connection | Total number of explicitly closed connections (ext/mysqli only). | Examples of code snippets that cause an explicit close :
$link = new mysqli(...); $link->close(...) $link = new mysqli(...); $link->connect(...) |
implicit_close |
Connection | Total number of implicitly closed connections (ext/mysqli only). | Examples of code snippets that cause an implicit close :
|
disconnect_close |
Connection | Connection failures indicated by the C API call mysql_real_connect() during an attempt to establish a connection. | It is called disconnect_close because the connection
handle passed to the C API call will be closed. |
in_middle_of_command_close |
Process | A connection has been closed in the middle of a command execution (outstanding result sets not fetched, after sending a query and before retrieving an answer, while fetching data, while transferring data with LOAD DATA). | Unless you use asynchronous queries this should only happen if your script stops unexpectedly and PHP shuts down the connections for you. |
init_command_executed_count |
Connection | Total number of init command executions, for example,
mysqli_options(MYSQLI_INIT_COMMAND , ...). |
The number of successful executions is
init_command_executed_count -
init_command_failed_count. |
init_command_failed_count |
Connection | Total number of failed init commands. |
| Statistic | Scope | Description | Notes |
|---|---|---|---|
com_quit, com_init_db,
com_query, com_field_list,
com_create_db, com_drop_db,
com_refresh, com_shutdown,
com_statistics,
com_process_info,
com_connect,
com_process_kill, com_debug,
com_ping, com_time,
com_delayed_insert,
com_change_user,
com_binlog_dump,
com_table_dump,
com_connect_out,
com_register_slave,
com_stmt_prepare,
com_stmt_execute,
com_stmt_send_long_data,
com_stmt_close,
com_stmt_reset,
com_stmt_set_option,
com_stmt_fetch, com_daemon |
Connection | Total number of attempts to send a certain COM_* command from PHP to MySQL. |
The statistics are incremented after checking the line and
immediately before sending the corresponding MySQL client server
protocol packet. If mysqlnd fails to send the packet over the
wire the statistics will not be decremented. In case of a failure
mysqlnd emits a PHP warning Usage examples:
|
Miscellaneous
| Statistic | Scope | Description | Notes |
|---|---|---|---|
explicit_stmt_close,
implicit_stmt_close |
Process | Total number of close prepared statements. | A close is always considered explicit but for a failed prepare. |
mem_emalloc_count,
mem_emalloc_ammount,
mem_ecalloc_count,
mem_ecalloc_ammount,
mem_erealloc_count,
mem_erealloc_ammount,
mem_efree_count,
mem_malloc_count,
mem_malloc_ammount,
mem_calloc_count,
mem_calloc_ammount,
mem_realloc_count,
mem_realloc_ammount,
mem_free_count |
Process | Memory management calls. | Development only. |
command_buffer_too_small |
Connection | Number of network command buffer extensions while sending commands from PHP to MySQL. |
mysqlnd allocates an internal command/network buffer of
If mysqlnd has to grow the buffer beyond its initial size of
The default buffer size is 2048 bytes in PHP 5.3.0. In future
versions the default will be 4kB or larger. The default can
changed either through the php.ini setting
It is recommended to set the buffer size to no less than 4096
bytes because mysqlnd also uses it when reading certain
communication packet from MySQL. In PHP 5.3.0, mysqlnd will not
grow the buffer if MySQL sends a packet that is larger than the
current size of the buffer. As a consequence mysqlnd is unable to
decode the packet and the client application will get an error.
There are only two situations when the packet can be larger than
the 2048 bytes default of
As of PHP 5.3.2 mysqlnd does not allow setting buffers smaller than 4096 bytes. |
connection_reused |
Notes
This section provides a collection of miscellaneous notes on MySQL Native Driver usage.
Using
mysqlndmeans using PHP streams for underlying connectivity. Formysqlnd, the PHP streams documentation (Streams) should be consulted on such details as timeout settings, not the documentation for the MySQL Client Library.
Memory management
Introduction
The MySQL Native Driver manages memory different than the MySQL Client Library. The libraries differ in the way memory is allocated and released, how memory is allocated in chunks while reading results from MySQL, which debug and development options exist, and how results read from MySQL are linked to PHP user variables.
The following notes are intended as an introduction and summary to users interested at understanding the MySQL Native Driver at the C code level.
Memory management functions used
All memory allocation and deallocation is done using the PHP memory management functions. Therefore, the memory consumption of mysqlnd can be tracked using PHP API calls, such as memory_get_usage(). Because memory is allocated and released using the PHP memory management, the changes may not immediately become visible at the operating system level. The PHP memory management acts as a proxy which may delay releasing memory towards the system. Due to this, comparing the memory usage of the MySQL Native Driver and the MySQL Client Library is difficult. The MySQL Client Library is using the operating system memory management calls directly, hence the effects can be observed immediately at the operating system level.
Any memory limit enforced by PHP also affects the MySQL Native Driver. This may cause out of memory errors when fetching large result sets that exceed the size of the remaining memory made available by PHP. Because the MySQL Client Library is not using PHP memory management functions, it does not comply to any PHP memory limit set. If using the MySQL Client Library, depending on the deployment model, the memory footprint of the PHP process may grow beyond the PHP memory limit. But also PHP scripts may be able to process larger result sets as parts of the memory allocated to hold the result sets are beyond the control of the PHP engine.
PHP memory management functions are invoked by the MySQL Native Driver through a lightweight wrapper. Among others, the wrapper makes debugging easier.
Handling of result sets
The various MySQL Server and the various client APIs differentiate between buffered and unbuffered result sets. Unbuffered result sets are transferred row-by-row from MySQL to the client as the client iterates over the results. Buffered results are fetched in their entirety by the client library before passing them on to the client.
The MySQL Native Driver is using PHP Streams for the network communication with the MySQL Server. Results sent by MySQL are fetched from the PHP Streams network buffers into the result buffer of mysqlnd. The result buffer is made of zvals. In a second step the results are made available to the PHP script. This final transfer from the result buffer into PHP variables impacts the memory consumption and is mostly noticeable when using buffered result sets.
By default the MySQL Native Driver tries to avoid holding buffered results twice in memory. Results are kept only once in the internal result buffers and their zvals. When results are fetched into PHP variables by the PHP script, the variables will reference the internal result buffers. Database query results are not copied and kept in memory only once. Should the user modify the contents of a variable holding the database results a copy-on-write must be performed to avoid changing the referenced internal result buffer. The contents of the buffer must not be modified because the user may decide to read the result set a second time. The copy-on-write mechanism is implemented using an additional reference management list and the use of standard zval reference counters. Copy-on-write must also be done if the user reads a result set into PHP variables and frees a result set before the variables are unset.
Generally speaking, this pattern works well for scripts that read a result set once and do not modify variables holding results. Its major drawback is the memory overhead caused by the additional reference management which comes primarily from the fact that user variables holding results cannot be entirely released until the mysqlnd reference management stops referencing them. The MySQL Native driver removes the reference to the user variables when the result set is freed or a copy-on-write is performed. An observer will see the total memory consumption grow until the result set is released. Use the statistics to check whether a script does release result sets explicitly or the driver is does implicit releases and thus memory is used for a time longer than necessary. Statistics also help to see how many copy-on-write operations happened.
A PHP script reading many small rows of a buffered result set using a code snippet
equal or equivalent to while ($row = $res->fetch_assoc()) { ... }
may optimize memory consumption by requesting copies instead of references.
Albeit requesting copies means keeping results twice in memory, it allows
PHP to free the copy contained in $row as the result set
is being iterated and prior to releasing the result set itself. On a loaded server
optimizing peak memory usage may help improving the overall system performance
although for an individual script the copy approach may be slower due to
additional allocations and memory copy operations.
The copy mode can be enforced by setting mysqlnd.fetch_data_copy=1.
Monitoring and debugging
There are multiple ways of tracking the memory usage of the MySQL Native Driver. If the goal is to get a quick high level overview or to verify the memory efficiency of PHP scripts, then check the statistics collected by the library. The statistics allow you, for example, to catch SQL statements which generate more results than are processed by a PHP script.
The debug trace log can be configured to record memory management calls. This helps to see when memory is allocated or free'd. However, the size of the requested memory chunks may not be listed.
Some, recent versions of the MySQL Native Driver feature the emulation of random out of memory situations. This feature is meant to be used by the C developers of the library or mysqlnd plugin authors only. Please, search the source code for corresponding PHP configuration settings and further details. The feature is considered private and may be modified at any time without prior notice.
MySQL Native Driver Plugin API
Table of Contents
- A comparison of mysqlnd plugins with MySQL Proxy
- Obtaining the mysqlnd plugin API
- MySQL Native Driver Plugin Architecture
- The mysqlnd plugin API
- Getting started building a mysqlnd plugin
The MySQL Native Driver Plugin API is a feature of MySQL Native
Driver, or mysqlnd. Mysqlnd
plugins operate in the layer between PHP applications and the MySQL
server. This is comparable to MySQL Proxy. MySQL Proxy operates on a
layer between any MySQL client application, for example, a PHP
application and, the MySQL server. Mysqlnd plugins
can undertake typical MySQL Proxy tasks such as load balancing,
monitoring and performance optimizations. Due to the different
architecture and location, mysqlnd plugins do not
have some of MySQL Proxy's disadvantages. For example, with plugins,
there is no single point of failure, no dedicated proxy server to
deploy, and no new programming language to learn (Lua).
A mysqlnd plugin can be thought of as an extension
to mysqlnd. Plugins can intercept the majority of
mysqlnd functions. The mysqlnd
functions are called by the PHP MySQL extensions such as
ext/mysql, ext/mysqli, and
PDO_MYSQL. As a result, it is possible for a
mysqlnd plugin to intercept all calls made to these
extensions from the client application.
Internal mysqlnd function calls can also be
intercepted, or replaced. There are no restrictions on manipulating
mysqlnd internal function tables. It is possible to
set things up so that when certain mysqlnd
functions are called by the extensions that use
mysqlnd, the call is directed to the appropriate
function in the mysqlnd plugin. The ability to
manipulate mysqlnd internal function tables in this
way allows maximum flexibility for plugins.
Mysqlnd plugins are in fact PHP Extensions, written
in C, that use the mysqlnd plugin API (which is
built into MySQL Native Driver, mysqlnd). Plugins
can be made 100% transparent to PHP applications. No application
changes are needed because plugins operate on a different layer. The
mysqlnd plugin can be thought of as operating in a
layer below mysqlnd.
The following list represents some possible applications of
mysqlnd plugins.
-
Load Balancing
-
Read/Write Splitting. An example of this is the PECL/mysqlnd_ms (Master Slave) extension. This extension splits read/write queries for a replication setup.
-
Failover
-
Round-Robin, least loaded
-
-
Monitoring
-
Query Logging
-
Query Analysis
-
Query Auditing. An example of this is the PECL/mysqlnd_sip (SQL Injection Protection) extension. This extension inspects queries and executes only those that are allowed according to a ruleset.
-
-
Performance
-
Caching. An example of this is the PECL/mysqlnd_qc (Query Cache) extension.
-
Throttling
-
Sharding. An example of this is the PECL/mysqlnd_mc (Multi Connect) extension. This extension will attempt to split a SELECT statement into n-parts, using SELECT ... LIMIT part_1, SELECT LIMIT part_n. It sends the queries to distinct MySQL servers and merges the result at the client.
-
MySQL Native Driver Plugins Available
There are a number of mysqlnd plugins already available. These include:
-
PECL/mysqlnd_mc - Multi Connect plugin.
-
PECL/mysqlnd_ms - Master Slave plugin.
-
PECL/mysqlnd_qc - Query Cache plugin.
-
PECL/mysqlnd_pscache - Prepared Statement Handle Cache plugin.
-
PECL/mysqlnd_sip - SQL Injection Protection plugin.
-
PECL/mysqlnd_uh - User Handler plugin.
A comparison of mysqlnd plugins with MySQL Proxy
Mysqlnd plugins and MySQL Proxy are different
technologies using different approaches. Both are valid tools for
solving a variety of common tasks such as load balancing, monitoring,
and performance enhancements. An important difference is that MySQL
Proxy works with all MySQL clients, whereas
mysqlnd plugins are specific to PHP applications.
As a PHP Extension, a mysqlnd plugin gets
installed on the PHP application server, along with the rest of PHP.
MySQL Proxy can either be run on the PHP application server or can be
installed on a dedicated machine to handle multiple PHP application
servers.
Deploying MySQL Proxy on the application server has two advantages:
-
No single point of failure
-
Easy to scale out (horizontal scale out, scale by client)
MySQL Proxy (and mysqlnd plugins) can solve
problems easily which otherwise would have required changes to
existing applications.
However, MySQL Proxy does have some disadvantages:
-
MySQL Proxy is a new component and technology to master and deploy.
-
MySQL Proxy requires knowledge of the Lua scripting language.
MySQL Proxy can be customized with C and Lua programming. Lua is the
preferred scripting language of MySQL Proxy. For most PHP experts Lua
is a new language to learn. A mysqlnd plugin can
be written in C. It is also possible to write plugins in PHP using
» PECL/mysqlnd_uh.
MySQL Proxy runs as a daemon - a background process. MySQL Proxy can
recall earlier decisions, as all state can be retained. However, a
mysqlnd plugin is bound to the request-based
lifecycle of PHP. MySQL Proxy can also share one-time computed
results among multiple application servers. A
mysqlnd plugin would need to store data in a
persistent medium to be able to do this. Another daemon would need to
be used for this purpose, such as Memcache. This gives MySQL Proxy an
advantage in this case.
MySQL Proxy works on top of the wire protocol. With MySQL Proxy you have to parse and reverse engineer the MySQL Client Server Protocol. Actions are limited to those that can be achieved by manipulating the communication protocol. If the wire protocol changes (which happens very rarely) MySQL Proxy scripts would need to be changed as well.
Mysqlnd plugins work on top of the C API, which
mirrors the libmysqlclient client.
This C API is basically a wrapper around the MySQL Client Server
protocol, or wire protocol, as it is sometimes called. You can
intercept all C API calls. PHP makes use of the C API, therefore you
can hook all PHP calls, without the need to program at the level of
the wire protocol.
Mysqlnd implements the wire protocol. Plugins can
therefore parse, reverse engineer, manipulate and even replace the
communication protocol. However, this is usually not required.
As plugins allow you to create implementations that use two levels (C
API and wire protocol), they have greater flexibility than MySQL
Proxy. If a mysqlnd plugin is implemented using
the C API, any subsequent changes to the wire protocol do not require
changes to the plugin itself.
Obtaining the mysqlnd plugin API
The mysqlnd plugin API is simply part of the MySQL
Native Driver PHP extension, ext/mysqlnd.
Development started on the mysqlnd plugin API in
December 2009. It is developed as part of the PHP source repository,
and as such is available to the public either via Git, or through
source snapshot downloads.
The following table shows PHP versions and the corresponding
mysqlnd version contained within.
| PHP Version | MySQL Native Driver version |
|---|---|
| 5.3.0 | 5.0.5 |
| 5.3.1 | 5.0.5 |
| 5.3.2 | 5.0.7 |
| 5.3.3 | 5.0.7 |
| 5.3.4 | 5.0.7 |
Plugin developers can determine the mysqlnd
version through accessing MYSQLND_VERSION, which
is a string of the format mysqlnd 5.0.7-dev - 091210 -
$Revision: 300535
, or through
MYSQLND_VERSION_ID, which is an integer such as
50007. Developers can calculate the version number as follows:
| Version (part) | Example |
|---|---|
| Major*10000 | 5*10000 = 50000 |
| Minor*100 | 0*100 = 0 |
| Patch | 7 = 7 |
| MYSQLND_VERSION_ID | 50007 |
During development, developers should refer to the
mysqlnd version number for compatibility and
version tests, as several iterations of mysqlnd
could occur during the lifetime of a PHP development branch with a
single PHP version number.
MySQL Native Driver Plugin Architecture
This section provides an overview of the mysqlnd
plugin architecture.
MySQL Native Driver Overview
Before developing mysqlnd plugins, it is useful to
know a little of how mysqlnd itself is organized.
Mysqlnd consists of the following modules:
| Modules Statistics | mysqlnd_statistics.c |
|---|---|
| Connection | mysqlnd.c |
| Resultset | mysqlnd_result.c |
| Resultset Metadata | mysqlnd_result_meta.c |
| Statement | mysqlnd_ps.c |
| Network | mysqlnd_net.c |
| Wire protocol | mysqlnd_wireprotocol.c |
C Object Oriented Paradigm
At the code level, mysqlnd uses a C pattern for
implementing object orientation.
In C you use a struct to represent an object.
Members of the struct represent object properties. Struct members
pointing to functions represent methods.
Unlike with other languages such as C++ or Java, there are no fixed rules on inheritance in the C object oriented paradigm. However, there are some conventions that need to be followed that will be discussed later.
The PHP Life Cycle
When considering the PHP life cycle there are two basic cycles:
-
PHP engine startup and shutdown cycle
-
Request cycle
When the PHP engine starts up it will call the module initialization (MINIT) function of each registered extension. This allows each module to setup variables and allocate resources that will exist for the lifetime of the PHP engine process. When the PHP engine shuts down it will call the module shutdown (MSHUTDOWN) function of each extension.
During the lifetime of the PHP engine it will receive a number of requests. Each request constitutes another life cycle. On each request the PHP engine will call the request initialization function of each extension. The extension can perform any variable setup and resource allocation required for request processing. As the request cycle ends the engine calls the request shutdown (RSHUTDOWN) function of each extension so the extension can perform any cleanup required.
How a plugin works
A mysqlnd plugin works by intercepting calls made
to mysqlnd by extensions that use
mysqlnd. This is achieved by obtaining the
mysqlnd function table, backing it up, and
replacing it by a custom function table, which calls the functions of
the plugin as required.
The following code shows how the mysqlnd function
table is replaced:
/* a place to store original function table */
struct st_mysqlnd_conn_methods org_methods;
void minit_register_hooks(TSRMLS_D) {
/* active function table */
struct st_mysqlnd_conn_methods * current_methods
= mysqlnd_conn_get_methods();
/* backup original function table */
memcpy(&org_methods, current_methods,
sizeof(struct st_mysqlnd_conn_methods);
/* install new methods */
current_methods->query = MYSQLND_METHOD(my_conn_class, query);
}
Connection function table manipulations must be done during Module Initialization (MINIT). The function table is a global shared resource. In an multi-threaded environment, with a TSRM build, the manipulation of a global shared resource during the request processing will almost certainly result in conflicts.
Note:
Do not use any fixed-size logic when manipulating the
mysqlndfunction table: new methods may be added at the end of the function table. The function table may change at any time in the future.
Calling parent methods
If the original function table entries are backed up, it is still possible to call the original function table entries - the parent methods.
In some cases, such as for
Connection::stmt_init(), it is vital to call the
parent method prior to any other activity in the derived method.
MYSQLND_METHOD(my_conn_class, query)(MYSQLND *conn,
const char *query, unsigned int query_len TSRMLS_DC) {
php_printf("my_conn_class::query(query = %s)\n", query);
query = "SELECT 'query rewritten' FROM DUAL";
query_len = strlen(query);
return org_methods.query(conn, query, query_len); /* return with call to parent */
}
Extending properties
A mysqlnd object is represented by a C struct. It
is not possible to add a member to a C struct at run time. Users of
mysqlnd objects cannot simply add properties to
the objects.
Arbitrary data (properties) can be added to a
mysqlnd objects using an appropriate function of
the
mysqlnd_plugin_get_plugin_<object>_data()
family. When allocating an object mysqlnd reserves
space at the end of the object to hold a void *
pointer to arbitrary data. mysqlnd reserves space
for one void * pointer per plugin.
The following table shows how to calculate the position of the pointer for a specific plugin:
| Memory address | Contents |
|---|---|
| 0 | Beginning of the mysqlnd object C struct |
| n | End of the mysqlnd object C struct |
| n + (m x sizeof(void*)) | void* to object data of the m-th plugin |
If you plan to subclass any of the mysqlnd object
constructors, which is allowed, you must keep this in mind!
The following code shows extending properties:
/* any data we want to associate */
typedef struct my_conn_properties {
unsigned long query_counter;
} MY_CONN_PROPERTIES;
/* plugin id */
unsigned int my_plugin_id;
void minit_register_hooks(TSRMLS_D) {
/* obtain unique plugin ID */
my_plugin_id = mysqlnd_plugin_register();
/* snip - see Extending Connection: methods */
}
static MY_CONN_PROPERTIES** get_conn_properties(const MYSQLND *conn TSRMLS_DC) {
MY_CONN_PROPERTIES** props;
props = (MY_CONN_PROPERTIES**)mysqlnd_plugin_get_plugin_connection_data(
conn, my_plugin_id);
if (!props || !(*props)) {
*props = mnd_pecalloc(1, sizeof(MY_CONN_PROPERTIES), conn->persistent);
(*props)->query_counter = 0;
}
return props;
}
The plugin developer is responsible for the management of plugin data memory.
Use of the mysqlnd memory allocator is recommended
for plugin data. These functions are named using the convention:
mnd_*loc(). The mysqlnd
allocator has some useful features, such as the ability to use a
debug allocator in a non-debug build.
| When to subclass? | Each instance has its own private function table? | How to subclass? | |
|---|---|---|---|
| Connection (MYSQLND) | MINIT | No | mysqlnd_conn_get_methods() |
| Resultset (MYSQLND_RES) | MINIT or later | Yes | mysqlnd_result_get_methods() or object method function table manipulation |
| Resultset Meta (MYSQLND_RES_METADATA) | MINIT | No | mysqlnd_result_metadata_get_methods() |
| Statement (MYSQLND_STMT) | MINIT | No | mysqlnd_stmt_get_methods() |
| Network (MYSQLND_NET) | MINIT or later | Yes | mysqlnd_net_get_methods() or object method function table manipulation |
| Wire protocol (MYSQLND_PROTOCOL) | MINIT or later | Yes | mysqlnd_protocol_get_methods() or object method function table manipulation |
You must not manipulate function tables at any time later than MINIT if it is not allowed according to the above table.
Some classes contain a pointer to the method function table. All instances of such a class will share the same function table. To avoid chaos, in particular in threaded environments, such function tables must only be manipulated during MINIT.
Other classes use copies of a globally shared function table. The class function table copy is created together with the object. Each object uses its own function table. This gives you two options: you can manipulate the default function table of an object at MINIT, and you can additionally refine methods of an object without impacting other instances of the same class.
The advantage of the shared function table approach is performance. There is no need to copy a function table for each and every object.
| Type | Allocation, construction, reset | Can be modified? | Caller |
|---|---|---|---|
| Connection (MYSQLND) | mysqlnd_init() | No | mysqlnd_connect() |
| Resultset(MYSQLND_RES) | Allocation:
Reset and re-initialized during:
|
Yes, but call parent! |
|
| Resultset Meta (MYSQLND_RES_METADATA) | Connection::result_meta_init() | Yes, but call parent! | Result::read_result_metadata() |
| Statement (MYSQLND_STMT) | Connection::stmt_init() | Yes, but call parent! | Connection::stmt_init() |
| Network (MYSQLND_NET) | mysqlnd_net_init() | No | Connection::init() |
| Wire protocol (MYSQLND_PROTOCOL) | mysqlnd_protocol_init() | No | Connection::init() |
It is strongly recommended that you do not entirely replace a
constructor. The constructors perform memory allocations. The memory
allocations are vital for the mysqlnd plugin API
and the object logic of mysqlnd. If you do not
care about warnings and insist on hooking the constructors, you
should at least call the parent constructor before doing anything in
your constructor.
Regardless of all warnings, it can be useful to subclass constructors. Constructors are the perfect place for modifying the function tables of objects with non-shared object tables, such as Resultset, Network, Wire Protocol.
| Type | Derived method must call parent? | Destructor |
|---|---|---|
| Connection | yes, after method execution | free_contents(), end_psession() |
| Resultset | yes, after method execution | free_result() |
| Resultset Meta | yes, after method execution | free() |
| Statement | yes, after method execution | dtor(), free_stmt_content() |
| Network | yes, after method execution | free() |
| Wire protocol | yes, after method execution | free() |
The destructors are the appropriate place to free properties,
mysqlnd_plugin_get_plugin_<object>_data().
The listed destructors may not be equivalent to the actual
mysqlnd method freeing the object itself. However,
they are the best possible place for you to hook in and free your
plugin data. As with constructors you may replace the methods
entirely but this is not recommended. If multiple methods are listed
in the above table you will need to hook all of the listed methods
and free your plugin data in whichever method is called first by
mysqlnd.
The recommended method for plugins is to simply hook the methods, free your memory and call the parent implementation immediately following this.
Due to a bug in PHP versions 5.3.0 to 5.3.3, plugins do not
associate plugin data with a persistent connection. This is because
ext/mysql and ext/mysqli do
not trigger all the necessary mysqlnd
end_psession() method calls and the plugin may
therefore leak memory. This has been fixed in PHP 5.3.4.
The mysqlnd plugin API
The following is a list of functions provided in the
mysqlnd plugin API:
-
mysqlnd_plugin_register()
-
mysqlnd_plugin_count()
-
mysqlnd_plugin_get_plugin_connection_data()
-
mysqlnd_plugin_get_plugin_result_data()
-
mysqlnd_plugin_get_plugin_stmt_data()
-
mysqlnd_plugin_get_plugin_net_data()
-
mysqlnd_plugin_get_plugin_protocol_data()
-
mysqlnd_conn_get_methods()
-
mysqlnd_result_get_methods()
-
mysqlnd_result_meta_get_methods()
-
mysqlnd_stmt_get_methods()
-
mysqlnd_net_get_methods()
-
mysqlnd_protocol_get_methods()
There is no formal definition of what a plugin is and how a plugin mechanism works.
Components often found in plugins mechanisms are:
-
A plugin manager
-
A plugin API
-
Application services (or modules)
-
Application service APIs (or module APIs)
The mysqlnd plugin concept employs these features,
and additionally enjoys an open architecture.
No Restrictions
A plugin has full access to the inner workings of
mysqlnd. There are no security limits or
restrictions. Everything can be overwritten to implement friendly or
hostile algorithms. It is recommended you only deploy plugins from a
trusted source.
As discussed previously, plugins can use pointers freely. These pointers are not restricted in any way, and can point into another plugin's data. Simple offset arithmetic can be used to read another plugin's data.
It is recommended that you write cooperative plugins, and that you
always call the parent method. The plugins should always cooperate
with mysqlnd itself.
| Extension | mysqlnd.query() pointer | call stack if calling parent |
|---|---|---|
| ext/mysqlnd | mysqlnd.query() | mysqlnd.query |
| ext/mysqlnd_cache | mysqlnd_cache.query() |
|
| ext/mysqlnd_monitor | mysqlnd_monitor.query() |
|
In this scenario, a cache (ext/mysqlnd_cache) and
a monitor (ext/mysqlnd_monitor) plugin are loaded.
Both subclass Connection::query(). Plugin
registration happens at MINIT using the logic
shown previously. PHP calls extensions in alphabetical order by
default. Plugins are not aware of each other and do not set extension
dependencies.
By default the plugins call the parent implementation of the query method in their derived version of the method.
PHP Extension Recap
This is a recap of what happens when using an example plugin,
ext/mysqlnd_plugin, which exposes the
mysqlnd C plugin API to PHP:
-
Any PHP MySQL application tries to establish a connection to 192.168.2.29
-
The PHP application will either use
ext/mysql,ext/mysqliorPDO_MYSQL. All three PHP MySQL extensions usemysqlndto establish the connection to 192.168.2.29. -
Mysqlndcalls its connect method, which has been subclassed byext/mysqlnd_plugin. -
ext/mysqlnd_plugincalls the userspace hookproxy::connect()registered by the user. -
The userspace hook changes the connection host IP from 192.168.2.29 to 127.0.0.1 and returns the connection established by
parent::connect(). -
ext/mysqlnd_pluginperforms the equivalent ofparent::connect(127.0.0.1)by calling the originalmysqlndmethod for establishing a connection. -
ext/mysqlndestablishes a connection and returns toext/mysqlnd_plugin.ext/mysqlnd_pluginreturns as well. -
Whatever PHP MySQL extension had been used by the application, it receives a connection to 127.0.0.1. The PHP MySQL extension itself returns to the PHP application. The circle is closed.
Getting started building a mysqlnd plugin
It is important to remember that a mysqlnd plugin
is itself a PHP extension.
The following code shows the basic structure of the MINIT function
that will be used in the typical mysqlnd plugin:
/* my_php_mysqlnd_plugin.c */
static PHP_MINIT_FUNCTION(mysqlnd_plugin) {
/* globals, ini entries, resources, classes */
/* register mysqlnd plugin */
mysqlnd_plugin_id = mysqlnd_plugin_register();
conn_m = mysqlnd_get_conn_methods();
memcpy(org_conn_m, conn_m,
sizeof(struct st_mysqlnd_conn_methods));
conn_m->query = MYSQLND_METHOD(mysqlnd_plugin_conn, query);
conn_m->connect = MYSQLND_METHOD(mysqlnd_plugin_conn, connect);
}
/* my_mysqlnd_plugin.c */
enum_func_status MYSQLND_METHOD(mysqlnd_plugin_conn, query)(/* ... */) {
/* ... */
}
enum_func_status MYSQLND_METHOD(mysqlnd_plugin_conn, connect)(/* ... */) {
/* ... */
}
Task analysis: from C to userspace
class proxy extends mysqlnd_plugin_connection {
public function connect($host, ...) { .. }
}
mysqlnd_plugin_set_conn_proxy(new proxy());
Process:
-
PHP: user registers plugin callback
-
PHP: user calls any PHP MySQL API to connect to MySQL
-
C: ext/*mysql* calls mysqlnd method
-
C: mysqlnd ends up in ext/mysqlnd_plugin
-
C: ext/mysqlnd_plugin
-
Calls userspace callback
-
Or original
mysqlndmethod, if userspace callback not set
-
You need to carry out the following:
-
Write a class "mysqlnd_plugin_connection" in C
-
Accept and register proxy object through "mysqlnd_plugin_set_conn_proxy()"
-
Call userspace proxy methods from C (optimization - zend_interfaces.h)
Userspace object methods can either be called using
call_user_function() or you can operate at a level
closer to the Zend Engine and use
zend_call_method().
Optimization: calling methods from C using zend_call_method
The following code snippet shows the prototype for the
zend_call_method function, taken from
zend_interfaces.h.
ZEND_API zval* zend_call_method(
zval **object_pp, zend_class_entry *obj_ce,
zend_function **fn_proxy, char *function_name,
int function_name_len, zval **retval_ptr_ptr,
int param_count, zval* arg1, zval* arg2 TSRMLS_DC
);
Zend API supports only two arguments. You may need more, for example:
enum_func_status (*func_mysqlnd_conn__connect)(
MYSQLND *conn, const char *host,
const char * user, const char * passwd,
unsigned int passwd_len, const char * db,
unsigned int db_len, unsigned int port,
const char * socket, unsigned int mysql_flags TSRMLS_DC
);
To get around this problem you will need to make a copy of
zend_call_method() and add a facility for
additional parameters. You can do this by creating a set of
MY_ZEND_CALL_METHOD_WRAPPER macros.
Calling PHP userspace
This code snippet shows the optimized method for calling a userspace function from C:
/* my_mysqlnd_plugin.c */
MYSQLND_METHOD(my_conn_class,connect)(
MYSQLND *conn, const char *host /* ... */ TSRMLS_DC) {
enum_func_status ret = FAIL;
zval * global_user_conn_proxy = fetch_userspace_proxy();
if (global_user_conn_proxy) {
/* call userspace proxy */
ret = MY_ZEND_CALL_METHOD_WRAPPER(global_user_conn_proxy, host, /*...*/);
} else {
/* or original mysqlnd method = do nothing, be transparent */
ret = org_methods.connect(conn, host, user, passwd,
passwd_len, db, db_len, port,
socket, mysql_flags TSRMLS_CC);
}
return ret;
}
Calling userspace: simple arguments
/* my_mysqlnd_plugin.c */
MYSQLND_METHOD(my_conn_class,connect)(
/* ... */, const char *host, /* ...*/) {
/* ... */
if (global_user_conn_proxy) {
/* ... */
zval* zv_host;
MAKE_STD_ZVAL(zv_host);
ZVAL_STRING(zv_host, host, 1);
MY_ZEND_CALL_METHOD_WRAPPER(global_user_conn_proxy, zv_retval, zv_host /*, ...*/);
zval_ptr_dtor(&zv_host);
/* ... */
}
/* ... */
}
Calling userspace: structs as arguments
/* my_mysqlnd_plugin.c */
MYSQLND_METHOD(my_conn_class, connect)(
MYSQLND *conn, /* ...*/) {
/* ... */
if (global_user_conn_proxy) {
/* ... */
zval* zv_conn;
ZEND_REGISTER_RESOURCE(zv_conn, (void *)conn, le_mysqlnd_plugin_conn);
MY_ZEND_CALL_METHOD_WRAPPER(global_user_conn_proxy, zv_retval, zv_conn, zv_host /*, ...*/);
zval_ptr_dtor(&zv_conn);
/* ... */
}
/* ... */
}
The first argument of many mysqlnd methods is a C
"object". For example, the first argument of the connect() method is
a pointer to MYSQLND. The struct MYSQLND
represents a mysqlnd connection object.
The mysqlnd connection object pointer can be
compared to a standard I/O file handle. Like a standard I/O file
handle a mysqlnd connection object shall be linked
to the userspace using the PHP resource variable type.
From C to userspace and back
class proxy extends mysqlnd_plugin_connection {
public function connect($conn, $host, ...) {
/* "pre" hook */
printf("Connecting to host = '%s'\n", $host);
debug_print_backtrace();
return parent::connect($conn);
}
public function query($conn, $query) {
/* "post" hook */
$ret = parent::query($conn, $query);
printf("Query = '%s'\n", $query);
return $ret;
}
}
mysqlnd_plugin_set_conn_proxy(new proxy());
PHP users must be able to call the parent implementation of an overwritten method.
As a result of subclassing it is possible to refine only selected methods and you can choose to have "pre" or "post" hooks.
Buildin class: mysqlnd_plugin_connection::connect()
/* my_mysqlnd_plugin_classes.c */
PHP_METHOD("mysqlnd_plugin_connection", connect) {
/* ... simplified! ... */
zval* mysqlnd_rsrc;
MYSQLND* conn;
char* host; int host_len;
if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "rs",
&mysqlnd_rsrc, &host, &host_len) == FAILURE) {
RETURN_NULL();
}
ZEND_FETCH_RESOURCE(conn, MYSQLND* conn, &mysqlnd_rsrc, -1,
"Mysqlnd Connection", le_mysqlnd_plugin_conn);
if (PASS == org_methods.connect(conn, host, /* simplified! */ TSRMLS_CC))
RETVAL_TRUE;
else
RETVAL_FALSE;
}
Mysqlnd replication and load balancing plugin
Introduction
The mysqlnd replication and load balancing plugin (mysqlnd_ms)
adds easy to use MySQL replication support to all PHP MySQL extensions that use
mysqlnd.
As of version PHP 5.3.3 the MySQL native driver for PHP
(mysqlnd)
features an internal plugin C API. C plugins, such as the replication and
load balancing plugin, can extend the functionality of
mysqlnd.
The MySQL native driver for PHP is a C library that ships together with PHP as of PHP 5.3.0. It serves as a drop-in replacement for the MySQL Client Library (libmysqlclient). Using mysqlnd has several advantages: no extra downloads are required because it's bundled with PHP, it's under the PHP license, there is lower memory consumption in certain cases, and it contains new functionality such as asynchronous queries.
Mysqlnd plugins like mysqlnd_ms operate, for the most part,
transparently from a user perspective. The replication and load balancing
plugin supports all PHP applications, and all MySQL PHP extensions.
It does not change existing APIs. Therefore, it can easily be used with
existing PHP applications.
Key Features
The key features of PECL/mysqlnd_ms are as follows.
-
Transparent and therefore easy to use.
-
Supports all of the PHP MySQL extensions.
-
SSL support.
-
A consistent API.
-
Little to no application changes required, dependent on the required usage scenario.
-
Lazy connections: connections to master and slave servers are not opened before a SQL statement is executed.
-
Optional: automatic use of master after the first write in a web request, to lower the possible impact of replication lag.
-
-
Can be used with any MySQL clustering solution.
-
MySQL Replication: Read-write splitting is done by the plugin. Primary focus of the plugin.
-
MySQL Cluster: Read-write splitting can be disabled. Configuration of multiple masters possible
-
Third-party solutions: the plugin is optimized for MySQL Replication but can be used with any other kind of MySQL clustering solution.
-
-
Featured read-write split strategies
-
Automatic detection of SELECT.
-
Supports SQL hints to overrule automatism.
-
User-defined.
-
Can be disabled for, for example, when using synchronous clusters such as MySQL Cluster.
-
-
Featured load balancing strategies
-
Round Robin: choose a different slave in round-robin fashion for every slave request.
-
Random: choose a random slave for every slave request.
-
Random once (sticky): choose a random slave once to run all slave requests for the duration of a web request.
-
User-defined. The application can register callbacks with mysqlnd_ms.
-
PHP 5.4.0 or newer: transaction aware when using API calls only to control transactions.
-
Weighted load balancing: servers can be assigned different priorities, for example, to direct more requests to a powerful machine than to another less powerful machine. Or, to prefer nearby machines to reduce latency.
-
-
Global transaction ID
-
Client-side emulation. Makes manual master server failover and slave promotion easier with asynchronous clusters, such as MySQL Replication.
-
Support for built-in global transaction identifier feature of MySQL 5.6.5 or newer.
-
Supports using transaction ids to identify up-to-date asynchronous slaves for reading when session consistency is required. Please, note the restrictions mentioned in the manual.
-
Throttling: optionally, the plugin can wait for a slave to become "synchronous" before continuing.
-
-
Service and consistency levels
-
Applications can request eventual, session and strong consistency service levels for connections. Appropriate cluster nodes will be searched automatically.
-
Eventual consistent MySQL Replication slave accesses can be replaced with fast local cache accesses transparently to reduce server load.
-
-
Partitioning and sharding
-
Servers of a replication cluster can be organized into groups. SQL hints can be used to manually direct queries to a specific group. Grouping can be used to partition (shard) the data, or to cure the issue of hotspots with updates.
-
MySQL Replication filters are supported through the table filter.
-
-
MySQL Fabric
-
Experimental support for MySQL Fabric is included.
-
Limitations
The built-in read-write-split mechanism is very basic. Every
query which starts with SELECT
is considered a read request to be sent to a MySQL slave server.
All other queries (such as SHOW statements)
are considered as write requests that are sent to the MySQL master server.
The build-in behavior can be overruled using
SQL hints, or a user-defined
callback function.
The read-write splitter is not aware of multi-statements. Multi-statements
are considered as one statement. The decision of where to run the statement
will be based on the beginning of the statement string. For example, if
using mysqli_multi_query()
to execute the multi-statement SELECT id FROM test ; INSERT INTO test(id) VALUES (1),
the statement will be redirected to a slave server because it begins with
SELECT. The INSERT statement, which is
also part of the multi-statement, will not be redirected to a master server.
Note:
Applications must be aware of the consequences of connection switches that are performed for load balancing purposes. Please check the documentation on connection pooling and switching, transaction handling, failover load balancing and read-write splitting.
On the name
The shortcut mysqlnd_ms
stands for mysqlnd master slave plugin. The name
was chosen for a quick-and-dirty proof-of-concept. In the beginning
the developers did not expect to continue using the code base.
Quickstart and Examples
Table of Contents
- Setup
- Running statements
- Connection state
- SQL Hints
- Local transactions
- XA/Distributed Transactions
- Service level and consistency
- Global transaction IDs
- Cache integration
- Failover
- Partitioning and Sharding
- MySQL Fabric
The mysqlnd replication load balancing plugin is easy to use. This quickstart will demo typical use-cases, and provide practical advice on getting started.
It is strongly recommended to read the reference sections in addition to the quickstart. The quickstart tries to avoid discussing theoretical concepts and limitations. Instead, it will link to the reference sections. It is safe to begin with the quickstart. However, before using the plugin in mission critical environments we urge you to read additionally the background information from the reference sections.
The focus is on using PECL mysqlnd_ms for work with an asynchronous MySQL cluster, namely MySQL replication. Generally speaking an asynchronous cluster is more difficult to use than a synchronous one. Thus, users of, for example, MySQL Cluster will find more information than needed.
Setup
The plugin is implemented as a PHP extension. See also the installation instructions to install the » PECL/mysqlnd_ms extension.
Compile or configure the PHP MySQL extension (API) (mysqli, PDO_MYSQL, mysql) that you plan to use with support for the mysqlnd library. PECL/mysqlnd_ms is a plugin for the mysqlnd library. To use the plugin with any of the PHP MySQL extensions, the extension has to use the mysqlnd library.
Then, load the extension into PHP and activate the plugin in the PHP configuration file using the PHP configuration directive named mysqlnd_ms.enable.
Example #1 Enabling the plugin (php.ini)
mysqlnd_ms.enable=1 mysqlnd_ms.config_file=/path/to/mysqlnd_ms_plugin.ini
The plugin uses its own configuration file. Use the PHP configuration directive mysqlnd_ms.config_file to set the full file path to the plugin-specific configuration file. This file must be readable by PHP (e.g., the web server user). Please note, the configuration directive mysqlnd_ms.config_file superseeds mysqlnd_ms.ini_file since 1.4.0. It is a common pitfall to use the old, no longer available configuration directive.
Create a plugin-specific configuration file. Save the file to the path set by the PHP configuration directive mysqlnd_ms.config_file.
The plugins configuration file
is JSON based. It is divided into one or more sections.
Each section has a name, for example, myapp. Every section
makes its own set of configuration settings.
A section must, at a minimum, list the MySQL replication master server, and set a list of slaves. The plugin supports using only one master server per section. Multi-master MySQL replication setups are not yet fully supported. Use the configuration setting master to set the hostname, and the port or socket of the MySQL master server. MySQL slave servers are configured using the slave keyword.
Example #2 Minimal plugin-specific configuration file (mysqlnd_ms_plugin.ini)
{
"myapp": {
"master": {
"master_0": {
"host": "localhost"
}
},
"slave": [
]
}
}
Configuring a MySQL slave server list is required, although it may contain an empty list. It is recommended to always configure at least one slave server.
Server lists can use
anonymous or non-anonymous syntax. Non-anonymous
lists include alias names for the servers, such as master_0
for the master in the above example. The quickstart uses the
more verbose non-anonymous syntax.
Example #3 Recommended minimal plugin-specific config (mysqlnd_ms_plugin.ini)
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "192.168.2.27",
"port": "3306"
}
}
}
}
If there are at least two servers in total, the plugin can start to load balance and switch connections. Switching connections is not always transparent and can cause issues in certain cases. The reference sections about connection pooling and switching, transaction handling, fail over load balancing and read-write splitting all provide more details. And potential pitfalls are described later in this guide.
It is the responsibility of the application to handle potential issues caused by connection switches, by configuring a master with at least one slave server, which allows switching to work therefore related problems can be found.
The MySQL master and MySQL slave servers, which you configure, do not need to be part of MySQL replication setup. For testing purpose you can use single MySQL server and make it known to the plugin as a master and slave server as shown below. This could help you to detect many potential issues with connection switches. However, such a setup will not be prone to the issues caused by replication lag.
Example #4 Using one server as a master and as a slave (testing only!)
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "127.0.0.1",
"port": "3306"
}
}
}
}
The plugin attempts to notify you of invalid configurations. Since 1.5.0 it will throw a warning during PHP startup if the configuration file cannot be read, is empty or parsing the JSON failed. Depending on your PHP settings those errors may appear in some log files only. Further validation is done when a connection is to be established and the configuration file is searched for valid sections. Setting mysqlnd_ms.force_config_usage may help debugging a faulty setup. Please, see also configuration file debugging notes.
Running statements
The plugin can be used with any PHP MySQL extension
(mysqli,
mysql, and
PDO_MYSQL) that is
compiled to use the mysqlnd library.
PECL/mysqlnd_ms plugs into the mysqlnd library.
It does not change the API or behavior of those extensions.
Whenever a connection to MySQL is being opened, the plugin compares the host
parameter value of the connect call, with the section names
from the plugin specific configuration file. If, for example, the
plugin specific configuration file has a section myapp then
the section should be referenced by opening a MySQL connection to the
host myapp
Example #1 Plugin specific configuration file (mysqlnd_ms_plugin.ini)
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "192.168.2.27",
"port": "3306"
}
}
}
}
Example #2 Opening a load balanced connection
<?php
/* Load balanced following "myapp" section rules from the plugins config file */
$mysqli = new mysqli("myapp", "username", "password", "database");
$pdo = new PDO('mysql:host=myapp;dbname=database', 'username', 'password');
$mysql = mysql_connect("myapp", "username", "password");
?>
The connection examples above will be load balanced.
The plugin will send read-only statements to the MySQL slave server with the
IP 192.168.2.27 and will listen on port 3306
for the MySQL client connection. All other statements will be directed to the
MySQL master server running on the host localhost. If on Unix like
operating systems, the master on localhost will be accepting
MySQL client connections on the Unix domain socket /tmp/mysql.sock,
while TCP/IP is the default port on Windows.
The plugin will use the user name username and the password
password to connect to any of the MySQL servers listed in
the section myapp of the plugins configuration file. Upon
connect, the plugin will select database as the current
schemata.
The username, password and schema name are taken from the connect
API calls and used for all servers. In other words: you must use the same
username and password for every MySQL server listed in a plugin configuration
file section. The is not a general limitation. As of PECL/mysqlnd_ms 1.1.0,
it is possible to set the
username and
password for any server in the
plugins configuration file, to be used instead of the credentials passed
to the API call.
The plugin does not change the API for running statements. Read-write splitting works out of the box. The following example assumes that there is no significant replication lag between the master and the slave.
Example #3 Executing statements
<?php
/* Load balanced following "myapp" section rules from the plugins config file */
$mysqli = new mysqli("myapp", "username", "password", "database");
if (mysqli_connect_errno()) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* Statements will be run on the master */
if (!$mysqli->query("DROP TABLE IF EXISTS test")) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
if (!$mysqli->query("CREATE TABLE test(id INT)")) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
if (!$mysqli->query("INSERT INTO test(id) VALUES (1)")) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
/* read-only: statement will be run on a slave */
if (!($res = $mysqli->query("SELECT id FROM test"))) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
} else {
$row = $res->fetch_assoc();
$res->close();
printf("Slave returns id = '%s'\n", $row['id']);
}
$mysqli->close();
?>
The above example will output something similar to:
Slave returns id = '1'
Connection state
The plugin changes the semantics of a PHP MySQL connection handle. A new connection handle represents a connection pool, instead of a single MySQL client-server network connection. The connection pool consists of a master connection, and optionally any number of slave connections.
Every connection from the connection pool has its own state. For example, SQL user variables, temporary tables and transactions are part of the state. For a complete list of items that belong to the state of a connection, see the connection pooling and switching concepts documentation. If the plugin decides to switch connections for load balancing, the application could be given a connection which has a different state. Applications must be made aware of this.
Example #1 Plugin config with one slave and one master
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "192.168.2.27",
"port": "3306"
}
}
}
}
Example #2 Pitfall: connection state and SQL user variables
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* Connection 1, connection bound SQL user variable, no SELECT thus run on master */
if (!$mysqli->query("SET @myrole='master'")) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
/* Connection 2, run on slave because SELECT */
if (!($res = $mysqli->query("SELECT @myrole AS _role"))) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
} else {
$row = $res->fetch_assoc();
$res->close();
printf("@myrole = '%s'\n", $row['_role']);
}
$mysqli->close();
?>
The above example will output:
@myrole = ''
The example opens a load balanced connection and executes two statements.
The first statement SET @myrole='master' does not begin
with the string SELECT. Therefore the plugin does not
recognize it as a read-only query which shall be run on a slave. The
plugin runs the statement on the connection to the master. The statement
sets a SQL user variable which is bound to the master connection. The
state of the master connection has been changed.
The next statement is SELECT @myrole AS _role.
The plugin does recognize it as a read-only query and sends it to
the slave. The statement is run on a connection to the slave. This
second connection does not have any SQL user variables bound to it.
It has a different state than the first connection to the master.
The requested SQL user variable is not set. The example script prints
@myrole = ''.
It is the responsibility of the application developer to take care of the connection state. The plugin does not monitor all connection state changing activities. Monitoring all possible cases would be a very CPU intensive task, if it could be done at all.
The pitfalls can easily be worked around using SQL hints.
SQL Hints
SQL hints can force a query to choose a specific server from the connection pool. It gives the plugin a hint to use a designated server, which can solve issues caused by connection switches and connection state.
SQL hints are standard compliant SQL comments. Because SQL comments are supposed to be ignored by SQL processing systems, they do not interfere with other programs such as the MySQL Server, the MySQL Proxy, or a firewall.
Three SQL hints are supported by the plugin: The
MYSQLND_MS_MASTER_SWITCH hint makes the plugin run a
statement on the master, MYSQLND_MS_SLAVE_SWITCH
enforces the use of the slave, and
MYSQLND_MS_LAST_USED_SWITCH will run a statement on
the same server that was used for the previous statement.
The plugin scans the beginning of a statement for the existence of an SQL hint. SQL hints are only recognized if they appear at the beginning of the statement.
Example #1 Plugin config with one slave and one master
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "192.168.2.27",
"port": "3306"
}
}
}
}
Example #2 SQL hints to prevent connection switches
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (mysqli_connect_errno()) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* Connection 1, connection bound SQL user variable, no SELECT thus run on master */
if (!$mysqli->query("SET @myrole='master'")) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
/* Connection 1, run on master because of SQL hint */
if (!($res = $mysqli->query(sprintf("/*%s*/SELECT @myrole AS _role", MYSQLND_MS_LAST_USED_SWITCH)))) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
} else {
$row = $res->fetch_assoc();
$res->close();
printf("@myrole = '%s'\n", $row['_role']);
}
$mysqli->close();
?>
The above example will output:
@myrole = 'master'
In the above example, using MYSQLND_MS_LAST_USED_SWITCH prevents
session switching from the master to a slave when running the SELECT
statement.
SQL hints can also be used to run SELECT statements
on the MySQL master server. This may be desired if the MySQL slave servers
are typically behind the master, but you need current data from the cluster.
In version 1.2.0 the concept of a service level has been introduced to address cases when current data is required. Using a service level requires less attention and removes the need of using SQL hints for this use case. Please, find more information below in the service level and consistency section.
Example #3 Fighting replication lag
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* Force use of master, master has always fresh and current data */
if (!$mysqli->query(sprintf("/*%s*/SELECT critical_data FROM important_table", MYSQLND_MS_MASTER_SWITCH))) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
?>
A use case may include the creation of tables on a slave.
If an SQL hint is not given, then the plugin will send CREATE
and INSERT statements to the master. Use the
SQL hint MYSQLND_MS_SLAVE_SWITCH if you want to
run any such statement on a slave, for example, to build temporary
reporting tables.
Example #4 Table creation on a slave
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* Force use of slave */
if (!$mysqli->query(sprintf("/*%s*/CREATE TABLE slave_reporting(id INT)", MYSQLND_MS_SLAVE_SWITCH))) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
/* Continue using this particular slave connection */
if (!$mysqli->query(sprintf("/*%s*/INSERT INTO slave_reporting(id) VALUES (1), (2), (3)", MYSQLND_MS_LAST_USED_SWITCH))) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
/* Don't use MYSQLND_MS_SLAVE_SWITCH which would allow switching to another slave! */
if ($res = $mysqli->query(sprintf("/*%s*/SELECT COUNT(*) AS _num FROM slave_reporting", MYSQLND_MS_LAST_USED_SWITCH))) {
$row = $res->fetch_assoc();
$res->close();
printf("There are %d rows in the table 'slave_reporting'", $row['_num']);
} else {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
$mysqli->close();
?>
The SQL hint MYSQLND_MS_LAST_USED forbids switching a
connection, and forces use of the previously used connection.
Local transactions
The current version of the plugin is not transaction safe by default, because it is not aware of running transactions in all cases. SQL transactions are units of work to be run on a single server. The plugin does not always know when the unit of work starts and when it ends. Therefore, the plugin may decide to switch connections in the middle of a transaction.
No kind of MySQL load balancer can detect transaction boundaries without any kind of hint from the application.
You can either use SQL hints to work around this limitation. Alternatively, you can activate transaction API call monitoring. In the latter case you must use API calls only to control transactions, see below.
Example #1 Plugin config with one slave and one master
[myapp]
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "192.168.2.27",
"port": "3306"
}
}
}
}
Example #2 Using SQL hints for transactions
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* Not a SELECT, will use master */
if (!$mysqli->query("START TRANSACTION")) {
/* Please use better error handling in your code */
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Prevent connection switch! */
if (!$mysqli->query(sprintf("/*%s*/INSERT INTO test(id) VALUES (1)", MYSQLND_MS_LAST_USED_SWITCH))) {
/* Please do proper ROLLBACK in your code, don't just die */
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
if ($res = $mysqli->query(sprintf("/*%s*/SELECT COUNT(*) AS _num FROM test", MYSQLND_MS_LAST_USED_SWITCH))) {
$row = $res->fetch_assoc();
$res->close();
if ($row['_num'] > 1000) {
if (!$mysqli->query(sprintf("/*%s*/INSERT INTO events(task) VALUES ('cleanup')", MYSQLND_MS_LAST_USED_SWITCH))) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
}
} else {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
if (!$mysqli->query(sprintf("/*%s*/UPDATE log SET last_update = NOW()", MYSQLND_MS_LAST_USED_SWITCH))) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
if (!$mysqli->query(sprintf("/*%s*/COMMIT", MYSQLND_MS_LAST_USED_SWITCH))) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
$mysqli->close();
?>
Starting with PHP 5.4.0, the mysqlnd library allows the
plugin to monitor the status of the autocommit mode, if
the mode is set by API calls instead of using SQL statements such as
SET AUTOCOMMIT=0. This makes it possible for the plugin to
become transaction aware. In this case, you do not need to use SQL hints.
If using PHP 5.4.0 or newer, API calls that enable autocommit mode,
and when setting the plugin configuration option
trx_stickiness=master,
the plugin can automatically disable load balancing and connection switches
for SQL transactions. In this configuration, the plugin stops load balancing
if autocommit is disabled and directs all statements to
the master. This prevents connection switches in the middle of
a transaction. Once autocommit is re-enabled, the plugin
starts to load balance statements again.
API based transaction boundary detection has been improved with PHP 5.5.0 and
PECL/mysqlnd_ms 1.5.0 to cover not only calls to mysqli_autocommit()
but also mysqli_begin(),
mysqli_commit() and mysqli_rollback().
Example #3 Transaction aware load balancing: trx_stickiness setting
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "127.0.0.1",
"port": "3306"
}
},
"trx_stickiness": "master"
}
}
Example #4 Transaction aware
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* Disable autocommit, plugin will run all statements on the master */
$mysqli->autocommit(false);
if (!$mysqli->query("INSERT INTO test(id) VALUES (1)")) {
/* Please do proper ROLLBACK in your code, don't just die */
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
if ($res = $mysqli->query("SELECT COUNT(*) AS _num FROM test")) {
$row = $res->fetch_assoc();
$res->close();
if ($row['_num'] > 1000) {
if (!$mysqli->query("INSERT INTO events(task) VALUES ('cleanup')")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
}
} else {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
if (!$mysqli->query("UPDATE log SET last_update = NOW()")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
if (!$mysqli->commit()) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Plugin assumes that the transaction has ended and starts load balancing again */
$mysqli->autocommit(true);
$mysqli->close();
?>
Note: Version requirement
The plugin configuration option trx_stickiness=master requires PHP 5.4.0 or newer.
Please note the restrictions outlined in the transaction handling concepts section.
XA/Distributed Transactions
Note: Version requirement
XA related functions have been introduced in PECL mysqlnd_ms version 1.6.0-alpha.
Note: Early adaptors wanted
The feature is currently under development. There may be issues and/or feature limitations. Do not use in production environments, although early lab tests indicate reasonable quality.
Please, contact the development team if you are interested in this feature. We are looking for real life feedback to complement the feature.
XA transactions are a standardized method for executing transactions across multiple resources. Those resources can be databases or other transactional systems. The MySQL server supports XA SQL statements which allows users to carry out a distributed SQL transaction that spawns multiple database servers or any kind as long as they support the SQL statements too. In such a scenario it is in the responsibility of the user to coordinate the participating servers.
PECL/mysqlnd_ms can act as a transaction coordinator for a global (distributed, XA)
transaction carried out on MySQL servers only. As a transaction coordinator, the plugin
tracks all servers involved in a global transaction and transparently issues
appropriate SQL statements on the participants. The global transactions are controlled with
mysqlnd_ms_xa_begin(), mysqlnd_ms_xa_commit()
and mysqlnd_ms_xa_rollback(). SQL details are mostly hidden from
the application as is the need to track and coordinate participants.
Example #1 General pattern for XA transactions
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* start a global transaction */
$gtrid_id = "12345";
if (!mysqlnd_ms_xa_begin($mysqli, $gtrid_id)) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* run queries as usual: XA BEGIN will be injected upon running a query */
if (!$mysqli->query("INSERT INTO orders(order_id, item) VALUES (1, 'christmas tree, 1.8m')")) {
/* Either INSERT failed or the injected XA BEGIN failed */
if ('XA' == substr($mysqli->sqlstate, 0, 2)) {
printf("Global transaction/XA related failure, [%d] %s\n", $mysqli->errno, $mysqli->error);
} else {
printf("INSERT failed, [%d] %s\n", $mysqli->errno, $mysqli->error);
}
/* rollback global transaction */
mysqlnd_ms_xa_rollback($mysqli, $xid);
die("Stopping.");
}
/* continue carrying out queries on other servers, e.g. other shards */
/* commit the global transaction */
if (!mysqlnd_ms_xa_commit($mysqli, $xa_id)) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
?>
Unlike with local transactions, which are carried out on a single server, XA transactions have an identifier (xid) associated with them. The XA transaction identifier is composed of a global transaction identifier (gtrid), a branch qualifier (bqual) a format identifier (formatID). Only the global transaction identifier can and must be given when calling any of the plugins XA functions.
Once a global transaction has been started, the plugin begins tracking servers
until the global transaction ends. When a server is picked for query execution,
the plugin injects the SQL statement XA BEGIN prior to
executing the actual SQL statement on the server. XA BEGIN
makes the server participate in the global transaction. If the injected
SQL statement fails, the plugin will report the issue in reply to the query
execution function that was used. In the above example,
$mysqli->query("INSERT INTO orders(order_id, item) VALUES (1, 'christmas tree, 1.8m')")
would indicate such an error. You may want to check the errors SQL state code to
determine whether the actual query (here: INSERT) has failed
or the error is related to the global transaction. It is up to you to ignore the
failure to start the global transaction on a server and continue execution
without having the server participate in the global transaction.
Example #2 Local and global transactions are mutually exclusive
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* start a local transaction */
if (!$mysqli->begin_transaction()) {
die(sprintf("[%d/%s] %s\n", $mysqli->errno, $mysqli->sqlstate, $mysqli->error));
}
/* cannot start global transaction now - must end local transaction first */
$gtrid_id = "12345";
if (!mysqlnd_ms_xa_begin($mysqli, $gtrid_id)) {
die(sprintf("[%d/%s] %s\n", $mysqli->errno, $mysqli->sqlstate, $mysqli->error));
}
?>
The above example will output:
Warning: mysqlnd_ms_xa_begin(): (mysqlnd_ms) Some work is done outside global transaction. You must end the active local transaction first in ... on line ... [1400/XAE09] (mysqlnd_ms) Some work is done outside global transaction. You must end the active local transaction first
A global transaction cannot be started when a local transaction is active.
The plugin tries to detect this situation as early as possible, that is when
mysqlnd_ms_xa_begin() is called. If using API calls only to
control transactions, the plugin will know that a local transaction is open and
return an error for mysqlnd_ms_xa_begin(). However, note the
plugins limitations on detecting
transaction boundaries.. In the worst case, if using direct SQL
for local transactions (BEGIN,
COMMIT, ...), it may happen that an error is delayed
until some SQL is executed on a server.
To end a global transaction invoke mysqlnd_ms_xa_commit() or mysqlnd_ms_xa_rollback(). When a global transaction is ended all participants must be informed of the end. Therefore, PECL/mysqlnd_ms transparently issues appropriate XA related SQL statements on some or all of them. Any failure during this phase will cause an implicit rollback. The XA related API is intentionally kept simple here. A more complex API that gave more control would bare few, if any, advantages over a user implementation that issues all lower level XA SQL statements itself.
XA transactions use the two-phase commit protocol. The two-phase commit
protocol is a blocking protocol. There are cases when no progress can
be made, not even when using timeouts. Transaction coordinators
should survive their own failure, be able to detect blockades and break ties.
PECL/mysqlnd_ms takes the role of a transaction coordinator and can be
configured to survive its own crash to avoid issues with blocked MySQL servers.
Therefore, the plugin can and should be configured to use a persistent and crash-safe state
to allow garbage collection of unfinished, aborted global transactions.
A global transaction can be aborted in an open state if either the plugin fails (crashes)
or a connection from the plugin to a global transaction participant fails.
Example #3 Transaction coordinator state store
{
"myapp": {
"xa": {
"state_store": {
"participant_localhost_ip": "192.168.2.12",
"mysql": {
"host": "192.168.2.13",
"user": "root",
"password": "",
"db": "test",
"port": "3312",
"socket": null
}
}
},
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "192.168.2.14",
"port": "3306"
}
}
}
}
Currently, PECL/mysqlnd_ms supports only using MySQL database tables
as a state store. The SQL definitions of the tables are given in the
plugin configuration section.
Please, make sure to use a transactional and crash-safe
storage engine for the tables, such as InnoDB. InnoDB is the default
table engine in recent versions of the MySQL server. Make also sure
the database server itself is highly available.
If a state store has been configured, the plugin can perform a garbage collection.
During garbage collection it may be necessary to connect to a participant
of a failed global transaction. Thus, the state store holds a list of participants
and, among others, their host names. If the garbage collection is run
on another host but the one that has written a participant entry with the
host name localhost, then localhost
resolves to different machines. There are two solutions to the problem.
Either you do not configure any servers with the host name localhost but
configure an IP address (and port) or, you hint the garbage collection.
In the above example, localhost is used for
master_0, hence it may not resolve to the correct
host during garbage collection. However, participant_localhost_ip
is also set to hint the garbage collection that localhost
stands for the IP 192.168.2.12.
Service level and consistency
Note: Version requirement
Service levels have been introduced in PECL mysqlnd_ms version 1.2.0-alpha. mysqlnd_ms_set_qos() is available with PHP 5.4.0 or newer.
Different types of MySQL cluster solutions offer different service and data consistency levels to their users. An asynchronous MySQL replication cluster offers eventual consistency by default. A read executed on an asynchronous slave may return current, stale or no data at all, depending on whether the slave has replayed all changesets from the master or not.
Applications using an MySQL replication cluster need to be designed to work correctly with eventual consistent data. In some cases, however, stale data is not acceptable. In those cases only certain slaves or even only master accesses are allowed to achieve the required quality of service from the cluster.
As of PECL mysqlnd_ms 1.2.0 the plugin is capable of selecting MySQL replication nodes automatically that deliver session consistency or strong consistency. Session consistency means that one client can read its writes. Other clients may or may not see the clients' write. Strong consistency means that all clients will see all writes from the client.
Example #1 Session consistency: read your writes
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "127.0.0.1",
"port": "3306"
}
}
}
}
Example #2 Requesting session consistency
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* read-write splitting: master used */
if (!$mysqli->query("INSERT INTO orders(order_id, item) VALUES (1, 'christmas tree, 1.8m')")) {
/* Please use better error handling in your code */
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Request session consistency: read your writes */
if (!mysqlnd_ms_set_qos($mysqli, MYSQLND_MS_QOS_CONSISTENCY_SESSION)) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Plugin picks a node which has the changes, here: master */
if (!$res = $mysqli->query("SELECT item FROM orders WHERE order_id = 1")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
var_dump($res->fetch_assoc());
/* Back to eventual consistency: stale data allowed */
if (!mysqlnd_ms_set_qos($mysqli, MYSQLND_MS_QOS_CONSISTENCY_EVENTUAL)) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Plugin picks any slave, stale data is allowed */
if (!$res = $mysqli->query("SELECT item, price FROM specials")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
?>
Service levels can be set in the plugins configuration file and at runtime
using mysqlnd_ms_set_qos().
In the example the function is used to enforce
session consistency (read your writes) for all future statements until further notice.
The SELECT statement on the orders table
is run on the master to ensure the previous write can be seen by the client.
Read-write splitting logic has been adapted to fulfill the service level.
After the application has read its changes from the orders table
it returns to the default service level, which is eventual consistency. Eventual
consistency puts no restrictions on choosing a node for statement execution.
Thus, the SELECT statement on the specials
table is executed on a slave.
The new functionality supersedes the use of SQL hints and the
master_on_write configuration option. In many cases
mysqlnd_ms_set_qos() is easier to use, more powerful
improves portability.
Example #3 Maximum age/slave lag
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "127.0.0.1",
"port": "3306"
}
},
"failover" : "master"
}
}
Example #4 Limiting slave lag
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* Read from slaves lagging no more than four seconds */
$ret = mysqlnd_ms_set_qos(
$mysqli,
MYSQLND_MS_QOS_CONSISTENCY_EVENTUAL,
MYSQLND_MS_QOS_OPTION_AGE,
4
);
if (!$ret) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Plugin picks any slave, which may or may not have the changes */
if (!$res = $mysqli->query("SELECT item, price FROM daytrade")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Back to default: use of all slaves and masters permitted */
if (!mysqlnd_ms_set_qos($mysqli, MYSQLND_MS_QOS_CONSISTENCY_EVENTUAL)) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
?>
The eventual consistency service level can be used with an optional
parameter to set a maximum slave lag for choosing slaves. If set,
the plugin checks SHOW SLAVE STATUS for all
configured slaves. In case of the example, only slaves
for which Slave_IO_Running=Yes,
Slave_SQL_Running=Yes and
Seconds_Behind_Master <= 4
is true are considered for executing the statement
SELECT item, price FROM daytrade.
Checking SHOW SLAVE STATUS is done transparently from
an applications perspective. Errors, if any, are reported as
warnings. No error will be set on the connection handle. Even if all
SHOW SLAVE STATUS SQL statements executed by
the plugin fail, the execution of the users statement is not stopped, given
that master fail over is enabled. Thus, no application changes are required.
Note: Expensive and slow operation
Checking
SHOW SLAVE STATUSfor all slaves adds overhead to the application. It is an expensive and slow background operation. Try to minimize the use of it. Unfortunately, a MySQL replication cluster does not give clients the possibility to request a list of candidates from a central instance. Thus, a more efficient way of checking the slaves lag is not available.Please, note the limitations and properties of
SHOW SLAVE STATUSas explained in the MySQL reference manual.
To prevent mysqlnd_ms from emitting a warning if no slaves can be found that lag no more than the defined number of seconds behind the master, it is necessary to enable master fail over in the plugins configuration file. If no slaves can be found and fail over is turned on, the plugin picks a master for executing the statement.
If no slave can be found and fail over is turned off, the plugin emits a warning, it does not execute the statement and it sets an error on the connection.
Example #5 Fail over not set
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "127.0.0.1",
"port": "3306"
}
}
}
}
Example #6 No slave within time limit
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* Read from slaves lagging no more than four seconds */
$ret = mysqlnd_ms_set_qos(
$mysqli,
MYSQLND_MS_QOS_CONSISTENCY_EVENTUAL,
MYSQLND_MS_QOS_OPTION_AGE,
4
);
if (!$ret) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Plugin picks any slave, which may or may not have the changes */
if (!$res = $mysqli->query("SELECT item, price FROM daytrade")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Back to default: use of all slaves and masters permitted */
if (!mysqlnd_ms_set_qos($mysqli, MYSQLND_MS_QOS_CONSISTENCY_EVENTUAL)) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
?>
The above example will output:
PHP Warning: mysqli::query(): (mysqlnd_ms) Couldn't find the appropriate slave connection. 0 slaves to choose from. Something is wrong in %s on line %d PHP Warning: mysqli::query(): (mysqlnd_ms) No connection selected by the last filter in %s on line %d [2000] (mysqlnd_ms) No connection selected by the last filter
Global transaction IDs
Note: Version requirement
A client-side global transaction ID injection has been introduced in mysqlnd_ms version 1.2.0-alpha. The feature is not required for synchronous clusters, such as MySQL Cluster. Use it with asynchronous clusters such as classical MySQL replication.
As of MySQL 5.6.5-m8 release candidate the MySQL server features built-in global transaction identifiers. The MySQL built-in global transaction ID feature is supported by
PECL/mysqlnd_ms1.3.0-alpha or later. However, the final feature set found in MySQL 5.6 production releases to date is not sufficient to support the ideas discussed below in all cases. Please, see also the concepts section.
PECL/mysqlnd_ms can either use its own global transaction ID emulation or the
global transaction ID feature built-in to MySQL 5.6.5-m8 or later. From a developer
perspective the client-side and server-side approach offer the same features with
regards to service levels provided by PECL/mysqlnd_ms. Their differences
are discussed in the concepts section.
The quickstart first demonstrates the use of the client-side global transaction ID emulation
built-in to PECL/mysqlnd_ms before its show how to use the server-side counterpart.
The order ensures that the underlying idea is discussed first.
Idea and client-side emulation
In its most basic form a global transaction ID (GTID) is a counter in a table on the master. The counter is incremented whenever a transaction is committed on the master. Slaves replicate the table. The counter serves two purposes. In case of a master failure, it helps the database administrator to identify the most recent slave for promoting it to the new master. The most recent slave is the one with the highest counter value. Applications can use the global transaction ID to search for slaves which have replicated a certain write (identified by a global transaction ID) already.
PECL/mysqlnd_ms can inject SQL for every committed transaction to increment a GTID counter.
The so created GTID is accessible by the application to identify an applications
write operation. This enables the plugin to deliver session consistency (read your writes)
service level by not only querying masters but also slaves which have replicated
the change already. Read load is taken away from the master.
Client-side global transaction ID emulation has some limitations. Please, read the concepts section carefully to fully understand the principles and ideas behind it, before using in production environments. The background knowledge is not required to continue with the quickstart.
First, create a counter table on your master server and insert a record into it. The plugin does not assist creating the table. Database administrators must make sure it exists. Depending on the error reporting mode, the plugin will silently ignore the lack of the table or bail out.
Example #1 Create counter table on master
CREATE TABLE `trx` (
`trx_id` int(11) DEFAULT NULL,
`last_update` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=latin1
INSERT INTO `trx`(`trx_id`) VALUES (1);
In the plugins configuration file set the SQL to update the
global transaction ID table using on_commit
from the global_transaction_id_injection
section. Make sure the table name used for the UPDATE
statement is fully qualified. In the example,
test.trx is used to refer to table trx
in the schema (database) test. Use the table that was created in
the previous step. It is important to set the fully qualified table name
because the connection on which the injection is done may use a different
default database. Make sure the user that opens the connection
is allowed to execute the UPDATE.
Enable reporting of errors that may occur when mysqlnd_ms does global transaction ID injection.
Example #2 Plugin config: SQL for client-side GTID injection
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "127.0.0.1",
"port": "3306"
}
},
"global_transaction_id_injection":{
"on_commit":"UPDATE test.trx SET trx_id = trx_id + 1",
"report_error":true
}
}
}
Example #3 Transparent global transaction ID injection
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* auto commit mode, transaction on master, GTID must be incremented */
if (!$mysqli->query("DROP TABLE IF EXISTS test")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* auto commit mode, transaction on master, GTID must be incremented */
if (!$mysqli->query("CREATE TABLE test(id INT)")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* auto commit mode, transaction on master, GTID must be incremented */
if (!$mysqli->query("INSERT INTO test(id) VALUES (1)")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* auto commit mode, read on slave, no increment */
if (!($res = $mysqli->query("SELECT id FROM test"))) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
var_dump($res->fetch_assoc());
?>
The above example will output:
array(1) {
["id"]=>
string(1) "1"
}
The example runs three statements in auto commit mode on the master, causing
three transactions on the master. For every such statement, the plugin will
inject the configured UPDATE transparently before executing
the users SQL statement. When the script ends the global
transaction ID counter on the master has been incremented by three.
The fourth SQL statement executed in the example, a SELECT,
does not trigger an increment. Only transactions (writes) executed on a master
shall increment the GTID counter.
Note: SQL for global transaction ID: efficient solution wanted!
The SQL used for the client-side global transaction ID emulation is inefficient. It is optimized for clearity not for performance. Do not use it for production environments. Please, help finding an efficient solution for inclusion in the manual. We appreciate your input.
Example #4 Plugin config: SQL for fetching GTID
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "127.0.0.1",
"port": "3306"
}
},
"global_transaction_id_injection":{
"on_commit":"UPDATE test.trx SET trx_id = trx_id + 1",
"fetch_last_gtid" : "SELECT MAX(trx_id) FROM test.trx",
"report_error":true
}
}
}
Example #5 Obtaining GTID after injection
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* auto commit mode, transaction on master, GTID must be incremented */
if (!$mysqli->query("DROP TABLE IF EXISTS test")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
printf("GTID after transaction %s\n", mysqlnd_ms_get_last_gtid($mysqli));
/* auto commit mode, transaction on master, GTID must be incremented */
if (!$mysqli->query("CREATE TABLE test(id INT)")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
printf("GTID after transaction %s\n", mysqlnd_ms_get_last_gtid($mysqli));
?>
The above example will output:
GTID after transaction 7 GTID after transaction 8
Applications can ask PECL mysqlnd_ms for a global transaction ID which
belongs to the last write operation performed by the application.
The function mysqlnd_ms_get_last_gtid() returns the
GTID obtained when executing the SQL statement from
the fetch_last_gtid entry of the
global_transaction_id_injection section from
the plugins configuration file. The function may be called
after the GTID has been incremented.
Applications are adviced not to run the SQL statement themselves as this bares the risk of accidentally causing an implicit GTID increment. Also, if the function is used, it is easy to migrate an application from one SQL statement for fetching a transaction ID to another, for example, if any MySQL server ever features built-in global transaction ID support.
The quickstart shows a SQL statement which will return a GTID equal or greater
to that created for the previous statement. It is exactly the GTID created
for the previous statement if no other clients have incremented the GTID in the
time span between the statement execution and the SELECT
to fetch the GTID. Otherwise, it is greater.
Example #6 Plugin config: Checking for a certain GTID
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "127.0.0.1",
"port": "3306"
}
},
"global_transaction_id_injection":{
"on_commit":"UPDATE test.trx SET trx_id = trx_id + 1",
"fetch_last_gtid" : "SELECT MAX(trx_id) FROM test.trx",
"check_for_gtid" : "SELECT trx_id FROM test.trx WHERE trx_id >= #GTID",
"report_error":true
}
}
}
Example #7 Session consistency service level and GTID combined
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* auto commit mode, transaction on master, GTID must be incremented */
if ( !$mysqli->query("DROP TABLE IF EXISTS test")
|| !$mysqli->query("CREATE TABLE test(id INT)")
|| !$mysqli->query("INSERT INTO test(id) VALUES (1)")
) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* GTID as an identifier for the last write */
$gtid = mysqlnd_ms_get_last_gtid($mysqli);
/* Session consistency (read your writes): try to read from slaves not only master */
if (false == mysqlnd_ms_set_qos($mysqli, MYSQLND_MS_QOS_CONSISTENCY_SESSION, MYSQLND_MS_QOS_OPTION_GTID, $gtid)) {
die(sprintf("[006] [%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Either run on master or a slave which has replicated the INSERT */
if (!($res = $mysqli->query("SELECT id FROM test"))) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
var_dump($res->fetch_assoc());
?>
A GTID returned from mysqlnd_ms_get_last_gtid()
can be used as an option for the session consistency service level.
Session consistency delivers read your writes. Session consistency can
be requested by calling
mysqlnd_ms_set_qos().
In the example, the plugin will execute the SELECT
statement either on the master or on a slave which has replicated
the previous INSERT already.
PECL mysqlnd_ms will transparently check every configured slave if
it has replicated the INSERT by checking the slaves
GTID table. The check is done running the SQL set with the
check_for_gtid option from the
global_transaction_id_injection section of
the plugins configuration file. Please note, that this is a slow and
expensive procedure. Applications should try to use it sparsely and only
if read load on the master becomes to high otherwise.
Use of the server-side global transaction ID feature
Note: Insufficient server support in MySQL 5.6
The plugin has been developed against a pre-production version of MySQL 5.6. It turns out that all released production versions of MySQL 5.6 do not provide clients with enough information to enforce session consistency based on GTIDs. Please, read the concepts section for details.
Starting with MySQL 5.6.5-m8 the MySQL Replication system features server-side
global transaction IDs. Transaction identifiers are automatically generated and
maintained by the server. Users do not need to take care of maintaining them.
There is no need to setup any tables in advance, or for setting
on_commit. A client-side emulation is no longer needed.
Clients can continue to use global transaction identifier to achieve
session consistency when reading from MySQL Replication slaves in some cases but not all!
The algorithm works as described above. Different SQL statements must be configured for
fetch_last_gtid and check_for_gtid.
The statements are given below. Please note, MySQL 5.6.5-m8 is a development
version. Details of the server implementation may change in the future and require
adoption of the SQL statements shown.
Using the following configuration any of the above described functionality can be used together with the server-side global transaction ID feature. mysqlnd_ms_get_last_gtid() and mysqlnd_ms_set_qos() continue to work as described above. The only difference is that the server does not use a simple sequence number but a string containing of a server identifier and a sequence number. Thus, users cannot easily derive an order from GTIDs returned by mysqlnd_ms_get_last_gtid().
Example #8 Plugin config: using MySQL 5.6.5-m8 built-in GTID feature
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "127.0.0.1",
"port": "3306"
}
},
"global_transaction_id_injection":{
"fetch_last_gtid" : "SELECT @@GLOBAL.GTID_DONE AS trx_id FROM DUAL",
"check_for_gtid" : "SELECT GTID_SUBSET('#GTID', @@GLOBAL.GTID_DONE) AS trx_id FROM DUAL",
"report_error":true
}
}
}
Cache integration
Note: Version requirement, dependencies and status
Please, find more about version requirements, extension load order dependencies and the current status in the concepts section!
Databases clusters can deliver different levels of consistency. As of
PECL/mysqlnd_ms 1.2.0 it is possible to advice the plugin to consider only
cluster nodes that can deliver the consistency level requested. For example,
if using asynchronous MySQL Replication with its cluster-wide eventual
consistency, it is possible to request session consistency (read your writes)
at any time using mysqlnd_ms_set_quos(). Please, see also the
service level and consistency
introduction.
Example #1 Recap: quality of service to request read your writes
/* Request session consistency: read your writes */
if (!mysqlnd_ms_set_qos($mysqli, MYSQLND_MS_QOS_CONSISTENCY_SESSION))
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
Assuming PECL/mysqlnd has been explicitly told to deliver no consistency level higher than eventual consistency, it is possible to replace a database node read access with a client-side cache using time-to-live (TTL) as its invalidation strategy. Both the database node and the cache may or may not serve current data as this is what eventual consistency defines.
Replacing a database node read access with a local cache access can improve overall performance and lower the database load. If the cache entry is every reused by other clients than the one creating the cache entry, a database access is saved and thus database load is lowered. Furthermore, system performance can become better if computation and delivery of a database query is slower than a local cache access.
Example #2 Plugin config: no special entries for caching
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "127.0.0.1",
"port": "3306"
}
},
}
}
Example #3 Caching a slave request
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
if ( !$mysqli->query("DROP TABLE IF EXISTS test")
|| !$mysqli->query("CREATE TABLE test(id INT)")
|| !$mysqli->query("INSERT INTO test(id) VALUES (1)")
) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Explicitly allow eventual consistency and caching (TTL <= 60 seconds) */
if (false == mysqlnd_ms_set_qos($mysqli, MYSQLND_MS_QOS_CONSISTENCY_EVENTUAL, MYSQLND_MS_QOS_OPTION_CACHE, 60)) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* To make this example work, we must wait for a slave to catch up. Brute force style. */
$attempts = 0;
do {
/* check if slave has the table */
if ($res = $mysqli->query("SELECT id FROM test")) {
break;
} else if ($mysqli->errno) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* wait for slave to catch up */
usleep(200000);
} while ($attempts++ < 10);
/* Query has been run on a slave, result is in the cache */
assert($res);
var_dump($res->fetch_assoc());
/* Served from cache */
$res = $mysqli->query("SELECT id FROM test");
?>
The example shows how to use the cache feature. First, you have to set the quality of service to eventual consistency and explicitly allow for caching. This is done by calling mysqlnd_ms_set_qos(). Then, the result set of every read-only statement is cached for upto that many seconds as allowed with mysqlnd_ms_set_qos().
The actual TTL is lower or equal to the value set with mysqlnd_ms_set_qos(). The value passed to the function sets the maximum age (seconds) of the data delivered. To calculate the actual TTL value the replication lag on a slave is checked and subtracted from the given value. If, for example, the maximum age is set to 60 seconds and the slave reports a lag of 10 seconds the resulting TTL is 50 seconds. The TTL is calculated individually for every cached query.
Example #4 Read your writes and caching combined
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
if ( !$mysqli->query("DROP TABLE IF EXISTS test")
|| !$mysqli->query("CREATE TABLE test(id INT)")
|| !$mysqli->query("INSERT INTO test(id) VALUES (1)")
) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Explicitly allow eventual consistency and caching (TTL <= 60 seconds) */
if (false == mysqlnd_ms_set_qos($mysqli, MYSQLND_MS_QOS_CONSISTENCY_EVENTUAL, MYSQLND_MS_QOS_OPTION_CACHE, 60)) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* To make this example work, we must wait for a slave to catch up. Brute force style. */
$attempts = 0;
do {
/* check if slave has the table */
if ($res = $mysqli->query("SELECT id FROM test")) {
break;
} else if ($mysqli->errno) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* wait for slave to catch up */
usleep(200000);
} while ($attempts++ < 10);
assert($res);
/* Query has been run on a slave, result is in the cache */
var_dump($res->fetch_assoc());
/* Served from cache */
if (!($res = $mysqli->query("SELECT id FROM test"))) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
var_dump($res->fetch_assoc());
/* Update on master */
if (!$mysqli->query("UPDATE test SET id = 2")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Read your writes */
if (false == mysqlnd_ms_set_qos($mysqli, MYSQLND_MS_QOS_CONSISTENCY_SESSION)) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Fetch latest data */
if (!($res = $mysqli->query("SELECT id FROM test"))) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
var_dump($res->fetch_assoc());
?>
The quality of service can be changed at any time to avoid further cache usage. If needed, you can switch to read your writes (session consistency). In that case, the cache will not be used and fresh data is read.
Failover
By default, the plugin does not attempt to fail over if connecting to a host fails. This prevents pitfalls related to connection state. It is recommended to manually handle connection errors in a way similar to a failed transaction. You should catch the error, rebuild the connection state and rerun your query as shown below.
If connection state is no issue to you, you can alternatively enable automatic and silent failover. Depending on the configuration, the automatic and silent failover will either attempt to fail over to the master before issuing and error or, try to connect to other slaves, given the query allowes for it, before attempting to connect to a master. Because automatic failover is not fool-proof, it is not discussed in the quickstart. Instead, details are given in the concepts section below.
Example #1 Manual failover, automatic optional
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "simulate_slave_failure",
"port": "0"
},
"slave_1": {
"host": "127.0.0.1",
"port": 3311
}
},
"filters": { "roundrobin": [] }
}
}
Example #2 Manual failover
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
$sql = "SELECT 1 FROM DUAL";
/* error handling as it should be done regardless of the plugin */
if (!($res = $link->query($sql))) {
/* plugin specific: check for connection error */
switch ($link->errno) {
case 2002:
case 2003:
case 2005:
printf("Connection error - trying next slave!\n");
/* load balancer will pick next slave */
$res = $link->query($sql);
break;
default:
/* no connection error, failover is unlikely to help */
die(sprintf("SQL error: [%d] %s", $link->errno, $link->error));
break;
}
}
if ($res) {
var_dump($res->fetch_assoc());
}
?>
Partitioning and Sharding
Database clustering is done for various reasons. Clusters can improve availability, fault tolerance, and increase performance by applying a divide and conquer approach as work is distributed over many machines. Clustering is sometimes combined with partitioning and sharding to further break up a large complex task into smaller, more manageable units.
The mysqlnd_ms plugin aims to support a wide variety of MySQL database clusters. Some flavors of MySQL database clusters have built-in methods for partitioning and sharding, which could be transparent to use. The plugin supports the two most common approaches: MySQL Replication table filtering, and Sharding (application based partitioning).
MySQL Replication supports partitioning as filters that allow you to
create slaves that replicate all or specific databases of the master, or tables.
It is then in the responsibility of the application
to choose a slave according to the filter rules. You can either use the
mysqlnd_ms node_groups
filter to manually support this, or use the experimental table filter.
Manual partitioning or sharding is supported through the
node grouping filter, and SQL hints as of 1.5.0. The node_groups filter
lets you assign a symbolic name to a group of master and slave servers.
In the example, the master master_0 and slave_0
form a group with the name Partition_A. It is entirely
up to you to decide what makes up a group. For example, you may use node
groups for sharding, and use the group names to address shards
like Shard_A_Range_0_100.
Example #1 Cluster node groups
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "simulate_slave_failure",
"port": "0"
},
"slave_1": {
"host": "127.0.0.1",
"port": 3311
}
},
"filters": {
"node_groups": {
"Partition_A" : {
"master": ["master_0"],
"slave": ["slave_0"]
}
},
"roundrobin": []
}
}
}
Example #2 Manual partitioning using SQL hints
<?php
function select($mysqli, $msg, $hint = '')
{
/* Note: weak test, two connections to two servers may have the same thread id */
$sql = sprintf("SELECT CONNECTION_ID() AS _thread, '%s' AS _hint FROM DUAL", $msg);
if ($hint) {
$sql = $hint . $sql;
}
if (!($res = $mysqli->query($sql))) {
printf("[%d] %s", $mysqli->errno, $mysqli->error);
return false;
}
$row = $res->fetch_assoc();
printf("%d - %s - %s\n", $row['_thread'], $row['_hint'], $sql);
return true;
}
$mysqli = new mysqli("myapp", "user", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* All slaves allowed */
select($mysqli, "slave_0");
select($mysqli, "slave_1");
/* only servers of node group "Partition_A" allowed */
select($mysqli, "slave_1", "/*Partition_A*/");
select($mysqli, "slave_1", "/*Partition_A*/");
?>
6804 - slave_0 - SELECT CONNECTION_ID() AS _thread, 'slave1' AS _hint FROM DUAL 2442 - slave_1 - SELECT CONNECTION_ID() AS _thread, 'slave2' AS _hint FROM DUAL 6804 - slave_0 - /*Partition_A*/SELECT CONNECTION_ID() AS _thread, 'slave1' AS _hint FROM DUAL 6804 - slave_0 - /*Partition_A*/SELECT CONNECTION_ID() AS _thread, 'slave1' AS _hint FROM DUAL
By default, the plugin will use all configured master and slave servers for
query execution. But if a query begins with a SQL hint like
/*node_group*/, the plugin will only consider the servers
listed in the node_group for query execution. Thus,
SELECT queries prefixed with /*Partition_A*/
will only be executed on slave_0.
MySQL Fabric
Note: Version requirement and status
Work on supporting MySQL Fabric started in version 1.6. Please, consider the support to be of pre-alpha quality. The manual may not list all features or feature limitations. This is work in progress.
Sharding is the only use case supported by the plugin to date.
Note: MySQL Fabric concepts
Please, check the MySQL reference manual for more information about MySQL Fabric and how to set it up. The PHP manual assumes that you are familiar with the basic concepts and ideas of MySQL Fabric.
MySQL Fabric is a system for managing farms of MySQL servers to achive High Availability and optionally support sharding. Technically, it is a middleware to manage and monitor MySQL servers.
Clients query MySQL Fabric to obtain lists of MySQL servers, their state and their roles. For example, clients can request a list of slaves for a MySQL Replication group and whether they are ready to handle SQL requests. Another example is a cluster of sharded MySQL servers where the client seeks to know which shard to query for a given table and shard key. If configured to use Fabric, the plugin uses XML RCP over HTTP to obtain the list at runtime from a MySQL Fabric host. The XML remote procedure call itself is done in the background and transparent from a developers point of view.
Instead of listing MySQL servers directly in the plugins configuration file it contains a list of one or more MySQL Fabric hosts
Example #1 Plugin config: Fabric hosts instead of MySQL servers
{
"myapp": {
"fabric": {
"hosts": [
{
"host" : "127.0.0.1",
"port" : 8080
}
]
}
}
}
Users utilize the new functions mysqlnd_ms_fabric_select_shard() and mysqlnd_ms_fabric_select_global() to switch to the set of servers responsible for a given shard key. Then, the plugin picks an appropriate server for running queries on. When doing so, the plugin takes care of additional load balancing rules set.
The below example assumes that MySQL Fabric has been setup
to shard the table test.fabrictest using
the id column of the table as a shard key.
Example #2 Manual partitioning using SQL hints
<?php
$mysqli = new mysqli("myapp", "user", "password", "database");
if (!$mysqli) {
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
}
/* Create a global table - a table available on all shards */
mysqlnd_ms_fabric_select_global($mysqli, "test.fabrictest");
if (!$mysqli->query("CREATE TABLE test.fabrictest(id INT NOT NULL PRIMARY KEY)")) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Switch connection to appropriate shard and insert record */
mysqlnd_ms_fabric_select_shard($mysqli, "test.fabrictest", 10);
if (!($res = $mysqli->query("INSERT INTO fabrictest(id) VALUES (10)"))) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
/* Try to read newly inserted record */
mysqlnd_ms_fabric_select_shard($mysqli, "test.fabrictest", 10);
if (!($res = $mysqli->query("SELECT id FROM test WHERE id = 10"))) {
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
}
?>
The example creates the sharded table, inserts a record and reads the record thereafter. All SQL data definition language (DDL) operations on a sharded table must be applied to the so called global server group. Prior to creating or altering a sharded table, mysqlnd_ms_fabric_select_global() is called to switch the given connection to the corresponding servers of the global group. Data manipulation (DML) SQL statements must be sent to the shards directly. The mysqlnd_ms_fabric_select_shard() switches a connection to shards handling a certain shard key.
Concepts
Table of Contents
- Architecture
- Connection pooling and switching
- Local transaction handling
- Error handling
- Transient errors
- Failover
- Load balancing
- Read-write splitting
- Filter
- Service level and consistency
- Global transaction IDs
- Cache integration
- Supported clusters
- XA/Distributed transactions
This explains the architecture and related concepts for this plugin, and describes the impact that MySQL replication and this plugin have on developmental tasks while using a database cluster. Reading and understanding these concepts is required, in order to use this plugin with success.
Architecture
The mysqlnd replication and load balancing plugin is implemented as a PHP extension. It is written in C and operates under the hood of PHP. During the startup of the PHP interpreter, in the module init phase of the PHP engine, it gets registered as a mysqlnd plugin to replace selected mysqlnd C methods.
At PHP runtime, it inspects queries sent from
mysqlnd (PHP) to the MySQL server. If a query is recognized as read-only,
it will be sent to one of the configured slave servers. Statements are
considered read-only if they either start with SELECT,
the SQL hint /*ms=slave*/ or a slave had been chosen for
running the previous query, and the query started with the SQL hint
/*ms=last_used*/. In all other cases, the query will
be sent to the MySQL replication master server.
For better portability, applications should use the
MYSQLND_MS_MASTER_SWITCH,
MYSQLND_MS_SLAVE_SWITCH, and
MYSQLND_MS_LAST_USED_SWITCH
predefined mysqlnd_ms constants,
instead of their literal values, such as /*ms=slave*/.
The plugin handles the opening and closing of database connections to both master and slave servers. From an application point of view, there continues to be only one connection handle. However, internally, this one public connection handle represents a pool of network connections that are managed by the plugin. The plugin proxies queries to the master server, and to the slaves using multiple connections.
Database connections have a state consisting of, for example, transaction
status, transaction settings, character set settings, and temporary tables.
The plugin will try to maintain the same state among all internal
connections, whenever this can be done in an automatic and transparent way.
In cases where it is not easily possible to maintain state among all
connections, such as when using BEGIN TRANSACTION, the
plugin leaves it to the user to handle.
Connection pooling and switching
The replication and load balancing plugin changes the semantics of a PHP MySQL connection handle. The existing API of the PHP MySQL extensions (mysqli, mysql, and PDO_MYSQL) are not changed in a way that functions are added or removed. But their behavior changes when using the plugin. Existing applications do not need to be adapted to a new API, but they may need to be modified because of the behavior changes.
The plugin breaks the one-by-one relationship between a mysqli, mysql, and PDO_MYSQL connection handle and a MySQL network connection. And a mysqli, mysql, and PDO_MYSQL connection handle represents a local pool of connections to the configured MySQL replication master and MySQL replication slave servers. The plugin redirects queries to the master and slave servers. At some point in time one and the same PHP connection handle may point to the MySQL master server. Later on, it may point to one of the slave servers or still the master. Manipulating and replacing the network connection referenced by a PHP MySQL connection handle is not a transparent operation.
Every MySQL connection has a state. The state of the connections in the connection pool of the plugin can differ. Whenever the plugin switches from one wire connection to another, the current state of the user connection may change. The applications must be aware of this.
The following list shows what the connection state consists of. The list may not be complete.
- Transaction status
- Temporary tables
- Table locks
- Session system variables and session user variables
-
The current database set using
USEand other state chaining SQL commands - Prepared statements
-
HANDLERvariables -
Locks acquired with
GET_LOCK()
Connection switches happen right before queries are executed. The plugin does not switch the current connection until the next statement is executed.
Note: Replication issues
See also the MySQL reference manual chapter about » replication features and related issues. Some restrictions may not be related to the PHP plugin, but are properties of the MySQL replication system.
Broadcasted messages
The plugins philosophy is to align the state of connections in the pool only if the state is under full control of the plugin, or if it is necessary for security reasons. Just a few actions that change the state of the connection fall into this category.
The following is a list of connection client library calls that change state, and are broadcasted to all open connections in the connection pool.
If any of the listed calls below are to be executed, the plugin loops over all open master and slave connections. The loop continues until all servers have been contacted, and the loop does not break if a server indicates a failure. If possible, the failure will propagate to the called user API function, which may be detected depending on which underlying library function was triggered.
| Library call | Notes | Version |
|---|---|---|
change_user()
|
Called by the mysqli_change_user() user API call.
Also triggered upon reuse of a persistent mysqli
connection.
|
Since 1.0.0. |
select_db
|
Called by the following user API calls:
mysql_select_db(),
mysql_list_tables(),
mysql_db_query(),
mysql_list_fields(),
mysqli_select_db().
Note, that SQL USE is not monitored.
|
Since 1.0.0. |
set_charset()
|
Called by the following user API calls:
mysql_set_charset().
mysqli_set_charset().
Note, that SQL SET NAMES is not monitored.
|
Since 1.0.0. |
set_server_option()
|
Called by the following user API calls: mysqli_multi_query(), mysqli_real_query(), mysqli_query(), mysql_query(). | Since 1.0.0. |
set_client_option()
|
Called by the following user API calls: mysqli_options(), mysqli_ssl_set(), mysqli_connect(), mysql_connect(), mysql_pconnect(). | Since 1.0.0. |
set_autocommit()
|
Called by the following user API calls:
mysqli_autocommit(),
PDO::setAttribute(PDO::ATTR_AUTOCOMMIT).
|
Since 1.0.0. PHP >= 5.4.0. |
ssl_set()
|
Called by the following user API calls: mysqli_ssl_set(). | Since 1.1.0. |
Broadcasting and lazy connections
The plugin does not proxy or
remember
all settings to apply them on connections
opened in the future. This is important to remember, if
using
lazy connections.
Lazy connections are connections which are not
opened before the client sends the first connection.
Use of lazy connections is the default plugin action.
The following connection library calls each changed state, and their execution is recorded for later use when lazy connections are opened. This helps ensure that the connection state of all connections in the connection pool are comparable.
| Library call | Notes | Version |
|---|---|---|
change_user()
|
User, password and database recorded for future use. | Since 1.1.0. |
select_db
|
Database recorded for future use. | Since 1.1.0. |
set_charset()
|
Calls set_client_option(MYSQL_SET_CHARSET_NAME, charset)
on lazy connection to ensure charset will be used
upon opening the lazy connection.
|
Since 1.1.0. |
set_autocommit()
|
Adds SET AUTOCOMMIT=0|1 to the list of init commands
of a lazy connection using
set_client_option(MYSQL_INIT_COMMAND, "SET AUTOCOMMIT=...%quot;).
|
Since 1.1.0. PHP >= 5.4.0. |
Connection state
The connection state is not only changed by API calls. Thus, even if PECL mysqlnd_ms monitors all API calls, the application must still be aware. Ultimately, it is the applications responsibility to maintain the connection state, if needed.
Charsets and string escaping
Due to the use of lazy connections, which are a default, it can happen that an application tries to escape a string for use within SQL statements before a connection has been established. In this case string escaping is not possible. The string escape function does not know what charset to use before a connection has been established.
To overcome the problem a new configuration setting
server_charset
has been introduced in version 1.4.0.
Attention has to be paid on escaping strings with a certain charset but using
the result on a connection that uses a different charset. Please note,
that PECL/mysqlnd_ms manipulates connections and one application level connection
represents a pool of multiple connections that all may have different default charsets.
It is recommended to configure the servers involved to use the same default charsets.
The configuration setting server_charset does help with this situation as well.
If using server_charset, the plugin will set the given
charset on all newly opened connections.
Local transaction handling
Transaction handling is fundamentally changed. An SQL transaction is a unit of work that is run on one database server. The unit of work consists of one or more SQL statements.
By default the plugin is not aware of SQL transactions. The plugin may switch connections for load balancing at any point in time. Connection switches may happen in the middle of a transaction. This is against the nature of an SQL transaction. By default, the plugin is not transaction safe.
Any kind of MySQL load balancer must be hinted about the begin and end of a transaction. Hinting can either be done implicitly by monitoring API calls or using SQL hints. Both options are supported by the plugin, depending on your PHP version. API monitoring requires PHP 5.4.0 or newer. The plugin, like any other MySQL load balancer, cannot detect transaction boundaries based on the MySQL Client Server Protocol. Thus, entirely transparent transaction aware load balancing is not possible. The least intrusive option is API monitoring, which requires little to no application changes, depending on your application.
Please, find examples of using SQL hints or the API monitoring in the examples section. The details behind the API monitoring, which makes the plugin transaction aware, are described below.
Beginning with PHP 5.4.0, the mysqlnd
library allows this plugin to subclass the library C API call
set_autocommit(), to detect the status of
autocommit mode.
The PHP MySQL extensions either issue a query (such as SET AUTOCOMMIT=0|1),
or use the mysqlnd library call set_autocommit() to control
the autocommit setting. If an extension makes use of
set_autocommit(), the plugin can be made transaction aware.
Transaction awareness cannot be achieved if using SQL to set the autocommit
mode.
The library function set_autocommit() is called by the
mysqli_autocommit() and
PDO::setAttribute(PDO::ATTR_AUTOCOMMIT) user API calls.
The plugin configuration option trx_stickiness=master can be used to make the plugin transactional aware. In this mode, the plugin stops load balancing if autocommit becomes disabled, and directs all statements to the master until autocommit gets enabled.
An application that does not want to set SQL hints for transactions but wants to use the transparent API monitoring to avoid application changes must make sure that the autocommit settings is changed exclusively through the listed API calls.
API based transaction boundary detection has been improved with PHP 5.5.0 and PECL/mysqlnd_ms 1.5.0 to cover not only calls to mysqli_autocommit() but also mysqli_begin(), mysqli_commit() and mysqli_rollback().
Error handling
Applications using PECL/mysqlnd_ms should implement proper error handling for all user API calls. And because the plugin changes the semantics of a connection handle, API calls may return unexpected errors. If using the plugin on a connection handle that no longer represents an individual network connection, but a connection pool, an error code and error message will be set on the connection handle whenever an error occurs on any of the network connections behind.
If using lazy connections, which is the default, connections are not opened until they are needed for query execution. Therefore, an API call for a statement execution may return a connection error. In the example below, an error is provoked when trying to run a statement on a slave. Opening a slave connection fails because the plugin configuration file lists an invalid host name for the slave.
Example #1 Provoking a connection error
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": {
"slave_0": {
"host": "invalid_host_name",
}
},
"lazy_connections": 1
}
}
The explicit activation of lazy connections is for demonstration purpose only.
Example #2 Connection error on query execution
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (mysqli_connect_errno())
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
/* Connection 1, connection bound SQL user variable, no SELECT thus run on master */
if (!$mysqli->query("SET @myrole='master'")) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
/* Connection 2, run on slave because SELECT, provoke connection error */
if (!($res = $mysqli->query("SELECT @myrole AS _role"))) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
} else {
$row = $res->fetch_assoc();
$res->close();
printf("@myrole = '%s'\n", $row['_role']);
}
$mysqli->close();
?>
The above example will output something similar to:
PHP Warning: mysqli::query(): php_network_getaddresses: getaddrinfo failed: Name or service not known in %s on line %d PHP Warning: mysqli::query(): [2002] php_network_getaddresses: getaddrinfo failed: Name or service not known (trying to connect via tcp://invalid_host_name:3306) in %s on line %d [2002] php_network_getaddresses: getaddrinfo failed: Name or service not known
Applications are expected to handle possible connection errors by implementing proper error handling.
Depending on the use case, applications may want to handle connection errors
differently from other errors. Typical connection errors are
2002 (CR_CONNECTION_ERROR) - Can't connect to local MySQL server through socket '%s' (%d),
2003 (CR_CONN_HOST_ERROR) - Can't connect to MySQL server on '%s' (%d) and
2005 (CR_UNKNOWN_HOST) - Unknown MySQL server host '%s' (%d).
For example, the application may test for the error codes and manually
perform a fail over. The plugins philosophy is not to offer automatic fail over,
beyond master fail over, because fail over is not a transparent operation.
Example #3 Provoking a connection error
{
"myapp": {
"master": {
"master_0": {
"host": "localhost"
}
},
"slave": {
"slave_0": {
"host": "invalid_host_name"
},
"slave_1": {
"host": "192.168.78.136"
}
},
"lazy_connections": 1,
"filters": {
"roundrobin": [
]
}
}
}
Explicitly activating lazy connections is done for demonstration purposes,
as is round robin load balancing as opposed to the default random once
type.
Example #4 Most basic failover
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (mysqli_connect_errno())
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
/* Connection 1, connection bound SQL user variable, no SELECT thus run on master */
if (!$mysqli->query("SET @myrole='master'")) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
/* Connection 2, first slave */
$res = $mysqli->query("SELECT VERSION() AS _version");
/* Hackish manual fail over */
if (2002 == $mysqli->errno || 2003 == $mysqli->errno || 2004 == $mysqli->errno) {
/* Connection 3, first slave connection failed, trying next slave */
$res = $mysqli->query("SELECT VERSION() AS _version");
}
if (!$res) {
printf("ERROR, [%d] '%s'\n", $mysqli->errno, $mysqli->error);
} else {
/* Error messages are taken from connection 3, thus no error */
printf("SUCCESS, [%d] '%s'\n", $mysqli->errno, $mysqli->error);
$row = $res->fetch_assoc();
$res->close();
printf("version = %s\n", $row['_version']);
}
$mysqli->close();
?>
The above example will output something similar to:
[1045] Access denied for user 'username'@'localhost' (using password: YES) PHP Warning: mysqli::query(): php_network_getaddresses: getaddrinfo failed: Name or service not known in %s on line %d PHP Warning: mysqli::query(): [2002] php_network_getaddresses: getaddrinfo failed: Name or service not known (trying to connect via tcp://invalid_host_name:3306) in %s on line %d SUCCESS, [0] '' version = 5.6.2-m5-log
In some cases, it may not be easily possible to retrieve all errors that occur on all network connections through a connection handle. For example, let's assume a connection handle represents a pool of three open connections. One connection to a master and two connections to the slaves. The application changes the current database using the user API call mysqli_select_db(), which then calls the mysqlnd library function to change the schemata. mysqlnd_ms monitors the function, and tries to change the current database on all connections to harmonize their state. Now, assume the master succeeds in changing the database, and both slaves fail. Upon the initial error from the first slave, the plugin will set an appropriate error on the connection handle. The same is done when the second slave fails to change the database. The error message from the first slave is lost.
Such cases can be debugged by either checking for errors of the type
E_WARNING (see above) or, if no other option, investigation
of the mysqlnd_ms debug and trace log.
Transient errors
Some distributed database clusters make use of transient errors. A transient error is a temporary error that is likely to disappear soon. By definition it is safe for a client to ignore a transient error and retry the failed operation on the same database server. The retry is free of side effects. Clients are not forced to abort their work or to fail over to another database server immediately. They may enter a retry loop before to wait for the error to disappear before giving up on the database server. Transient errors can be seen, for example, when using MySQL Cluster. But they are not bound to any specific clustering solution per se.
PECL/mysqlnd_ms can perform an automatic retry loop in
case of a transient error. This increases distribution transparency and thus
makes it easier to migrate an application running on a single database
server to run on a cluster of database servers without having to change
the source of the application.
The automatic retry loop will repeat the requested operation up to a user configurable number of times and pause between the attempts for a configurable amount of time. If the error disappears during the loop, the application will never see it. If not, the error is forwarded to the application for handling.
In the example below a duplicate key error is provoked to make the plugin retry the failing query two times before the error is passed to the application. Between the two attempts the plugin sleeps for 100 milliseconds.
Example #1 Provoking a transient error
mysqlnd_ms.enable=1 mysqlnd_ms.collect_statistics=1
{
"myapp": {
"master": {
"master_0": {
"host": "localhost"
}
},
"slave": {
"slave_0": {
"host": "192.168.78.136",
"port": "3306"
}
},
"transient_error": {
"mysql_error_codes": [
1062
],
"max_retries": 2,
"usleep_retry": 100
}
}
}
Example #2 Transient error retry loop
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
if (mysqli_connect_errno())
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
if (!$mysqli->query("DROP TABLE IF EXISTS test") ||
!$mysqli->query("CREATE TABLE test(id INT PRIMARY KEY)") ||
!$mysqli->query("INSERT INTO test(id) VALUES (1))")) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
/* Retry loop is completely transparent. Checking statistics is
the only way to know about implicit retries */
$stats = mysqlnd_ms_get_stats();
printf("Transient error retries before error: %d\n", $stats['transient_error_retries']);
/* Provoking duplicate key error to see statistics change */
if (!$mysqli->query("INSERT INTO test(id) VALUES (1))")) {
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
$stats = mysqlnd_ms_get_stats();
printf("Transient error retries after error: %d\n", $stats['transient_error_retries']);
$mysqli->close();
?>
The above example will output something similar to:
Transient error retries before error: 0 [1062] Duplicate entry '1' for key 'PRIMARY' Transient error retries before error: 2
Because the execution of the retry loop is transparent from a users point of view, the example checks the statistics provided by the plugin to learn about it.
As the example shows, the plugin can be instructed to consider any error
transient regardless of the database servers error semantics. The only error
that a stock MySQL server considers temporary has the error code
1297. When configuring other error codes but
1297 make sure your configuration reflects
the semantics of your clusters error codes.
The following mysqlnd C API calls are monitored by the plugin to check
for transient errors: query(),
change_user(), select_db(),
set_charset(), set_server_option()
prepare(), execute(),
set_autocommit(),
tx_begin(), tx_commit(),
tx_rollback(), tx_commit_or_rollback().
The corresponding user API calls have similar names.
The maximum time the plugin may sleep during the retry loop depends on the
function in question. The a retry loop for query(),
prepare() or execute() will sleep for
up to max_retries * usleep_retry milliseconds.
However, functions that
control connection state
are dispatched to all connections. The retry loop settings are applied
to every connection on which the command is to be run. Thus, such a function
may interrupt program execution for longer than a function that is run
on one server only. For example, set_autocommit() is
dispatched to connections and may sleep up to
(max_retries * usleep_retry) * number_of_open_connections)
milliseconds. Please, keep this in mind when setting long sleep times
and large retry numbers. Using the default settings of
max_retries=1, usleep_retry=100 and
lazy_connections=1 it is unlikely that you will
ever see a delay of more than 1 second.
Failover
By default, connection failover handling is left to the user. The application is responsible for checking return values of the database functions it calls and reacting to possible errors. If, for example, the plugin recognizes a query as a read-only query to be sent to the slave servers, and the slave server selected by the plugin is not available, the plugin will raise an error after not executing the statement.
Default: manual failover
It is up to the application to handle the error and, if required, re-issue the query to trigger the selection of another slave server for statement execution. The plugin will make no attempts to failover automatically, because the plugin cannot ensure that an automatic failover will not change the state of the connection. For example, the application may have issued a query which depends on SQL user variables which are bound to a specific connection. Such a query might return incorrect results if the plugin would switch the connection implicitly as part of automatic failover. To ensure correct results, the application must take care of the failover, and rebuild the required connection state. Therefore, by default, no automatic failover is performed by the plugin.
A user that does not change the connection state after opening a connection may activate automatic failover. Please note, that automatic failover logic is limited to connection attempts. Automatic failover is not used for already established connections. There is no way to instruct the plugin to attempt failover on a connection that has been connected to MySQL already in the past.
Automatic failover
The failover policy is configured in the plugins configuration file, by using the failover configuration directive.
Automatic and silent failover can be enabled through the failover configuration directive. Automatic failover can either be configured to try exactly one master after a slave failure or, alternatively, loop over slaves and masters before returning an error to the user. The number of connection attempts can be limited and failed hosts can be excluded from future load balancing attempts. Limiting the number of retries and remembering failed hosts are considered experimental features, albeit being reasonable stable. Syntax and semantics may change in future versions.
Please note, since version 1.5.0 automatic failover is disabled for the
duration of a transaction if transaction stickiness is enabled and
transaction boundaries have been detected. The plugin will not switch
connections for the duration of a transaction. It will also not perform
automatic and silent failover. Instead an error will be thrown. It is then left
to the user to handle the failure of the transaction. Please check, the
trx_stickiness
documentation how to do this.
A basic manual failover example is provided within the error handling section.
Standby servers
Using weighted load balancing, introduced in PECL/mysqlnd 1.4.0, it is possible to configure standby servers that are sparsely used during normal operations. A standby server that is primarily used as a worst-case standby failover target can be assigned a very low weight/priority in relation to all other servers. As long as all servers are up and running the majority of the workload is assigned to the servers which have hight weight values. Few requests will be directed to the standby system which has a very low weight value.
Upon failure of the servers with a high priority, you can still failover to
the standby, which has been given a low load balancing priority by assigning a low
weight to it. Failover can be some manually or automatically. If done
automatically, you may want to combine it with the
remember_failed
option.
At this point, it is not possible to instruct the load balancer to direct no requests at all to a standby. This may not be much of a limitation given that the highest weight you can assign to a server is 65535. Given two slaves, of which one shall act as a standby and has been assigned a weight of 1, the standby will have to handle far less than one percent of the overall workload.
Failover and primary copy
Please note, if using a primary copy cluster, such as MySQL Replication, it is difficult to do connection failover in case of a master failure. At any time there is only one master in the cluster for a given dataset. The master is a single point of failure. If the master fails, clients have no target to fail over write requests. In case of a master outage the database administrator must take care of the situation and update the client configurations, if need be.
Load balancing
Four load balancing strategies are supported to distribute statements over the configured MySQL slave servers:
- random
-
Chooses a random server whenever a statement is executed.
- random once (default)
-
Chooses a random server after the first statement is executed, and uses the decision for the rest of the PHP request.
It is the default, and the lowest impact on the connection state.
- round robin
-
Iterates over the list of configured servers.
- user-defined via callback
-
Is used to implement any other strategy.
The load balancing policy is configured in the plugins configuration file using the random, roundrobin, and user filters.
Servers can be prioritized assigning a weight. A server that has been given a weight of two will get twice as many requests as a server that has been given the default weight of one. Prioritization can be handy in heterogenous environments. For example, you may want to assign more requests to a powerful machine than to a less powerful. Or, you may have configured servers that are close or far from the client, thus expose different latencies.
Read-write splitting
The plugin executes read-only statements on the configured MySQL slaves, and
all other queries on the MySQL master. Statements are
considered read-only if they either start with SELECT,
the SQL hint /*ms=slave*/, or if a slave had been chosen for
running the previous query and the query starts with the SQL hint
/*ms=last_used*/. In all other cases, the query will
be sent to the MySQL replication master server. It is recommended to
use the constants MYSQLND_MS_SLAVE_SWITCH,
MYSQLND_MS_MASTER_SWITCH and MYSQLND_MS_LAST_USED_SWITCH
instead of /*ms=slave*/. See also the
list of mysqlnd_ms constants.
SQL hints are a special kind of standard compliant SQL comments. The plugin does check every statement for certain SQL hints. The SQL hints are described within the mysqlnd_ms constants documentation, constants that are exported by the extension. Other systems involved with the statement processing, such as the MySQL server, SQL firewalls, and SQL proxies, are unaffected by the SQL hints, because those systems are designed to ignore SQL comments.
The built-in read-write splitter can be replaced by a user-defined filter, see also the user filter documentation.
A user-defined read-write splitter can request the built-in logic to send a statement to a specific location, by invoking mysqlnd_ms_is_select().
Note:
The built-in read-write splitter is not aware of multi-statements. Multi-statements are seen as one statement. The splitter will check the beginning of the statement to decide where to run the statement. If, for example, a multi-statement begins with
SELECT 1 FROM DUAL; INSERT INTO test(id) VALUES (1); ...the plugin will run it on a slave although the statement is not read-only.
Filter
Note: Version requirement
Filters exist as of mysqlnd_ms version 1.1.0-beta.
filters. PHP applications that implement a MySQL replication cluster must first identify a group of servers in the cluster which could execute a statement before the statement is executed by one of the candidates. In other words: a defined list of servers must be filtered until only one server is available.
The process of filtering may include using one or more filters, and filters can be chained. And they are executed in the order they are defined in the plugins configuration file.
Note: Explanation: comparing filter chaining to pipes
The concept of chained filters can be compared to using pipes to connect command line utilities on an operating system command shell. For example, an input stream is passed to a processor, filtered, and then transferred to be output. Then, the output is passed as input to the next command, which is connected to the previous using the pipe operator.
Available filters:
- Load balancing filters: random and roundrobin.
- Selection filter: user, user_multi, quality_of_service.
The random filter implements the 'random' and 'random once'
load balancing policies. The 'round robin' load balancing can be configured
through the roundrobin filter. Setting a 'user defined
callback' for server selection is possible with the user
filter. The quality_of_service filter finds cluster
nodes capable of delivering a certain service, for example, read-your-writes or,
not lagging more seconds behind the master than allowed.
Filters can accept parameters to change their behavior.
The random filter accepts an optional
sticky parameter. If set to true, the filter changes
load balancing from random to random once. Random picks a random server
every time a statement is to be executed. Random once picks a random
server when the first statement is to be executed and uses the same
server for the rest of the PHP request.
One of the biggest strength of the filter concept is the possibility to
chain filters. This strength does not become immediately visible because
the random, roundrobin and
user filters are supposed to output no more than one server.
If a filter reduces the list of candidates for running a statement to
only one server, it makes little sense to use that one server as
input for another filter for further reduction of the list of candidates.
An example filter sequence that will fail:
-
Statement to be executed:
SELECT 1 FROM DUAL. Passed to all filters. -
All configured nodes are passed as input to the first filter.
Master nodes:
master_0. Slave nodes:slave_0,slave_1 -
Filter:
random, argumentsticky=1. Picks a random slave once to be used for the rest of the PHP request. Output:slave_0. -
Output of
slave_0and the statement to be executed is passed as input to the next filter. Here:roundrobin, server list passed to filter is:slave_0. -
Filter:
roundrobin. Server list consists of one server only, round robin will always return the same server.
(mysqlnd_ms) Error while creating
filter '%s' . Non-multi filter '%s' already created. Stopping in %s on
line %d. Furthermore, an appropriate error on the connection handle
may be set.
A second type of filter exists: multi filter. A multi filter emits zero, one or multiple
servers after processing. The quality_of_service filter
is an example. If the service quality requested sets an upper limit for the slave
lag and more than one slave is lagging behind less than the allowed number of seconds,
the filter returns more than one cluster node. A multi filter must be followed by other
to further reduce the list of candidates for statement execution until a candidate
is found.
A filter sequence with the quality_of_service
multi filter followed by a load balancing filter.
-
Statement to be executed:
SELECT sum(price) FROM orders WHERE order_id = 1. Passed to all filters. -
All configured nodes are passed as input to the first filter.
Master nodes:
master_0. Slave nodes:slave_0,slave_1,slave_2,slave_3 -
Filter:
quality_of_service, rule set: session_consistency (read-your-writes) Output:master_0 -
Output of
master_0and the statement to be executed is passed as input to the next filter, which isroundrobin. -
Filter:
roundrobin. Server list consists of one server. Round robin selectsmaster_0.
A filter sequence must not end with a multi filter. If trying to use
a filter sequence which ends with a multi filter the plugin may emit a
warning like (mysqlnd_ms) Error in configuration. Last filter is multi
filter. Needs to be non-multi one. Stopping in %s on line %d.
Furthermore, an appropriate error on the connection handle
may be set.
Note: Speculation towards the future: MySQL replication filtering
In future versions, there may be additional multi filters. For example, there may be a
tablefilter to support MySQL replication filtering. This would allow you to define rules for which database or table is to be replicated to which node of a replication cluster. Assume your replication cluster consists of four slaves (slave_0,slave_1,slave_2,slave_3) two of which replicate a database namedsales(slave_0,slave_1). If the application queries the databaseslaves, the hypotheticaltablefilter reduces the list of possible servers toslave_0andslave_1. Because the output and list of candidates consists of more than one server, it is necessary and possible to add additional filters to the candidate list, for example, using a load balancing filter to identify a server for statement execution.
Service level and consistency
Note: Version requirement
Service levels have been introduced in mysqlnd_ms version 1.2.0-alpha. mysqlnd_ms_set_qos() requires PHP 5.4.0 or newer.
The plugin can be used with different kinds of MySQL database clusters. Different clusters can deliver different levels of service to applications. The service levels can be grouped by the data consistency levels that can be achieved. The plugin knows about:
- eventual consistency
- session consistency
- strong consistency
Depending how a cluster is used it may be possible to achieve higher service levels than the default one. For example, a read from an asynchronous MySQL replication slave is eventual consistent. Thus, one may say the default consistency level of a MySQL replication cluster is eventual consistency. However, if the master only is used by a client for reading and writing during a session, session consistency (read your writes) is given. PECL mysqlnd 1.2.0 abstracts the details of choosing an appropriate node for any of the above service levels from the user.
Service levels can be set through the qualify-of-service filter in the plugins configuration file and at runtime using the function mysqlnd_ms_set_qos().
The plugin defines the different service levels as follows.
Eventual consistency is the default service provided by an asynchronous cluster, such as classical MySQL replication. A read operation executed on an arbitrary node may or may not return stale data. The applications view of the data is eventual consistent.
Session consistency is given if a client can always read its own writes. An asynchronous MySQL replication cluster can deliver session consistency if clients always use the master after the first write or never query a slave which has not yet replicated the clients write operation.
The plugins understanding of strong consistency is that all clients always see the committed writes of all other clients. This is the default when using MySQL Cluster or any other cluster offering synchronous data distribution.
Service level parameters
Eventual consistency and session consistency service level accept parameters.
Eventual consistency is the service provided by classical MySQL replication.
By default, all nodes qualify for read requests. An optional age
parameter can be given to filter out nodes which lag more than a certain number of
seconds behind the master. The plugin is using SHOW SLAVE STATUS
to measure the lag. Please, see the MySQL reference manual to learn about accuracy and
reliability of the SHOW SLAVE STATUS command.
Session consistency (read your writes) accepts an optional GTID
parameter to consider reading not only from the master but also from slaves
which already have replicated a certain write described by its transaction identifier.
This way, when using asynchronous MySQL replication, read requests may be load balanced
over slaves while still ensuring session consistency.
The latter requires the use of client-side global transaction id injection.
Advantages of the new approach
The new approach supersedes the use of SQL hints and the configuration option
master_on_write in some respects. If an application
running on top of an asynchronous MySQL replication cluster cannot accept stale
data for certain reads, it is easier to tell the plugin to choose appropriate
nodes than prefixing all read statements in question with the SQL hint
to enforce the use of the master. Furthermore, the plugin may be able to
use selected slaves for reading.
The master_on_write configuration option makes the plugin
use the master after the first write (session consistency, read your writes).
In some cases, session consistency may not be needed for the rest of the session
but only for some, few read operations. Thus, master_on_write
may result in more read load on the master than necessary. In those cases it
is better to request a higher than default service level only for those reads
that actually need it. Once the reads are done, the application can return to
default service level. Switching between service levels is only possible
using mysqlnd_ms_set_qos().
Performance considerations
A MySQL replication cluster cannot tell clients which slaves are capable of delivering which level of service. Thus, in some cases, clients need to query the slaves to check their status. PECL mysqlnd_ms transparently runs the necessary SQL in the background. However, this is an expensive and slow operation. SQL statements are run if eventual consistency is combined with an age (slave lag) limit and if session consistency is combined with a global transaction ID.
If eventual consistency is combined with an maximum age (slave lag), the plugin
selects candidates for statement execution and load balancing for each statement
as follows. If the statement is a write all masters are considered as candidates. Slaves
are not checked and not considered as candidates. If the statement is a read, the
plugin transparently executes SHOW SLAVE STATUS on every slaves
connection. It will loop over all connections, send the statement and then start
checking for results. Usually, this is slightly faster than a loop over all connections
in which for every connection a query is send and the plugin waits for its results.
A slave is considered a candidate if SHOW SLAVE STATUS reports
Slave_IO_Running=Yes,
Slave_SQL_Running=Yes and
Seconds_Behind_Master is less or equal than the allowed maximum age.
In case of an SQL error, the plugin emits a warning but does not set an error on
the connection. The error is not set to make it possible to use the plugin as a drop-in.
If session consistency is combined with a global transaction ID, the plugin executes
the SQL statement set with the fetch_last_gtid entry of the
global_transaction_id_injection section from the plugins configuration file.
Further details are identical to those described above.
In version 1.2.0 no additional optimizations are done for executing background queries. Future versions may contain optimizations, depending on user demand.
If no parameters and options are set, no SQL is needed. In that case, the plugin consider all nodes of the type shown below.
- eventual consistency, no further options set: all masters, all slaves
- session consistency, no further options set: all masters
- strong consistency (no options allowed): all masters
Throttling
The quality of service filter can be combined with Global transaction IDs to throttle clients. Throttling does reduce the write load on the master by slowing down clients. If session consistency is requested and global transactions identifier are used to check the status of a slave, the check can be done in two ways. By default a slave is checked and skipped immediately if it does not match the criteria for session consistency. Alternatively, the plugin can wait for a slave to catch up to the master until session consistency is possible. To enable the throttling, you have to set wait_for_gtid_timeout configuration option.
Global transaction IDs
Note: Version requirement
Client side global transaction ID injection exists as of mysqlnd_ms version 1.2.0-alpha. Transaction boundaries are detected by monitoring API calls. This is possible as of PHP 5.4.0. Please, see also Transaction handling.
As of MySQL 5.6.5-m8 the MySQL server features built-in global transaction identifiers. The MySQL built-in global transaction ID feature is supported by
PECL/mysqlnd_ms1.3.0-alpha or later. Neither are client-side transaction boundary monitoring nor any setup activities required if using the server feature.Please note, all MySQL 5.6 production versions do not provide clients with enough information to use GTIDs for enforcing session consistency. In the worst case, the plugin will choose the master only.
Idea and client-side emulation
PECL/mysqlnd_ms can do client-side transparent global transaction ID injection.
In its most basic form, a global transaction identifier is a counter which is
incremented for every transaction executed on the master. The counter is held
in a table on the master. Slaves replicate the counter table.
In case of a master failure a database administrator can easily identify the most recent slave for promoting it as a new master. The most recent slave has the highest transaction identifier.
Application developers can ask the plugin for the global transaction identifier (GTID) for their last successful write operation. The plugin will return an identifier that refers to an transaction no older than that of the clients last write operation. Then, the GTID can be passed as a parameter to the quality of service (QoS) filter as an option for session consistency. Session consistency ensures read your writes. The filter ensures that all reads are either directed to a master or a slave which has replicated the write referenced by the GTID.
When injection is done
The plugin transparently maintains the GTID table on the master.
In autocommit mode the plugin injects an UPDATE statement
before executing the users statement for every master use. In manual
transaction mode, the injection is done before the application calls
commit() to close a transaction. The configuration option
report_error of the GTID section in the plugins configuration
file is used to control whether a failed injection shall abort the current
operation or be ignored silently (default).
Please note, the PHP version requirements for transaction boundary monitoring and their limits.
Limitations
Client-side global transaction ID injection has shortcomings. The potential
issues are not specific to PECL/mysqlnd_ms
but are rather of general nature.
- Global transaction ID tables must be deployed on all masters and replicas.
- The GTID can have holes. Only PHP clients using the plugin will maintain the table. Other clients will not.
- Client-side transaction boundary detection is based on API calls only.
- Client-side transaction boundary detection does not take implicit commit into account. Some MySQL SQL statements cause an implicit commit and cannot be rolled back.
Using server-side global transaction identifier
Starting with PECL/mysqlnd_ms 1.3.0-alpha
the MySQL 5.6.5-m8 or newer built-in global
transaction identifier feature is supported. Use of the server feature lifts
all of the above listed limitations. Please, see the MySQL Reference Manual
for limitations and preconditions for using server built-in global transaction
identifiers.
Whether to use the client-side emulation or the server built-in functionality is a question not directly related to the plugin, thus it is not discussed in depth. There are no plans to remove the client-side emulation and you can continue to use it, if the server-side solution is no option. This may be the case in heterogenous environments with old MySQL server or, if any of the server-side solution limitations is not acceptable.
From an applications perspective there is hardly a difference in using one or the other approach. The following properties differ.
- Client-side emulation, as shown in the manual, is using an easy to compare sequence number for global transactions. Multi-master is not handled to keep the manual examples easy. Server-side built-in feature is using a combination of a server identifier and a sequence number as a global transaction identifier. Comparison cannot use numeric algebra. Instead a SQL function must be used. Please, see the MySQL Reference Manual for details. Server-side built-in feature of MySQL 5.6 cannot be used to ensure session consistency under all circumstances. Do not use it for the quality-of-service feature. Here is a simple example why it will not give reliable results. There are more edge cases that cannot be covered with limited functionality exported by the server. Currently, clients can ask a MySQL replication master for a list of all executed global transaction IDs only. If a slave is configured not to replicate all transactions, for example, because replication filters are set, then the slave will never show the same set of executed global transaction IDs. Albeit the slave may have replicated a clients writes and it may be a candidate for a consistent read, it will never be considered by the plugin. Upon write the plugin learns from the master that the servers complete transaction history consists of GTID=1..3. There is no way for the plugin to ask for the GTID of the write transaction itself, say GTID=3. Assume that a slave does not replicate the transactions GTID=1..2 but only GTID=3 because of a replication feature. Then, the slaves transaction history is GTID=3. However, the plugin tries to find a node which has a transaction history of GITD=1...3. Albeit the slave has replicated the clients write and session consistency may be achieved when reading from the slave, it will not be considered by the plugin. This is not a fault of the plugin implementation but a feature gap on the server side. Please note, this is a trivial case to illustrate the issue there are other issues. In sum you are asked not to attempt using MySQL 5.6 built-in GTIDs for enforcing session consistency. Sooner or later the load balancing will stop working properly and the plugin will direct all session consistency requests to the master.
- Plugin global transaction ID statistics are only available with client-side emulation because they monitor the emulation.
Note: Global transaction identifiers in distributed systems
Global transaction identifiers can serve multiple purposes in the context of distributed systems, such as a database cluster. Global transaction identifiers can be used for, for example, system wide identification of transactions, global ordering of transactions, heartbeat mechanism and for checking the replication status of replicas.
PECL/mysqlnd_ms, a clientside driver based software, does focus on using GTIDs for tasks that can be handled at the client, such as checking the replication status of replicas for asynchronous replication setups.
Cache integration
Note: Version requirement
The feature requires use of
PECL/mysqlnd_ms1.3.0-beta or later, andPECL/mysqlnd_qc1.1.0-alpha or newer.PECL/mysqlnd_msmust be compiled to support the feature. PHP 5.4.0 or newer is required.
Note: Setup: extension load order
PECL/mysqlnd_msmust be loaded beforePECL/mysqlnd_qc, when using shared extensions.
Note: Feature stability
The cache integration is of beta quality.
Note: Suitable MySQL clusters
The feature is targeted for use with MySQL Replication (primary copy). Currently, no other kinds of MySQL clusters are supported. Users of such cluster must control PECL/mysqlnd_qc manually if they are interested in client-side query caching.
Support for MySQL replication clusters (asynchronous primary copy) is the
main focus of PECL/mysqlnd_ms.
The slaves of a MySQL replication cluster
may or may not reflect the latest updates from the master.
Slaves are asynchronous and can lag behind the master. A read from a slave
is eventual consistent from a cluster-wide perspective.
The same level of consistency is offered by a local cache using time-to-live (TTL) invalidation strategy. Current data or stale data may be served. Eventually, data searched for in the cache is not available and the source of the cache needs to be accessed.
Given that both a MySQL Replication slave (asynchronous secondary) and a local TTL-driven cache deliver the same level of service it is possible to transparently replace a remote database access with a local cache access to gain better possibility.
As of PECL/mysqlnd_ms 1.3.0-beta the plugin is
capable of transparently controlling PECL/mysqlnd_ms 1.1.0-alpha
or newer to cache a read-only query if explicitly allowed by setting an
appropriate quality of service through mysqlnd_ms_set_qos(). P
lease, see the
quickstart for a code example.
Both plugins must be installed, PECL/mysqlnd_ms
must be compiled to support the cache feature and PHP 5.4.0 or newer has to be used.
Applications have full control of cache usage and can request fresh data at any time, if need be. The cache usage can be enabled and disabled time during the execution of a script. The cache will be used if mysqlnd_ms_set_qos() sets the quality of service to eventual consistency and enables cache usage. Cache usage is disabled by requesting higher consistency levels, for example, session consistency (read your writes). Once the quality of service has been relaxed to eventual consistency the cache can be used again.
If caching is enabled for a read-only statement, PECL/mysqlnd_ms may inject
SQL hints to control caching
by PECL/mysqlnd_qc. It may modify the SQL statement it got from the application.
Subsequent SQL processors are supposed to ignore the SQL hints. A SQL hint is a
SQL comment. Comments must not be ignored, for example, by the database server.
The TTL of a cache entry is computed on a per statement basis. Applications set an maximum age for the data they want to retrieve using mysqlnd_ms_set_qos(). The age sets an approximate upper limit of how many seconds the data returned may lag behind the master.
The following logic is used to compute the actual TTL if caching is enabled. The logic takes the estimated slave lag into account for choosing a TTL. If, for example, there are two slaves lagging 5 and 10 seconds behind and the maximum age allowed is 60 seconds, the TTL is set to 50 seconds. Please note, the age setting is no more than an estimated guess.
- Check whether the statement is read-only. If not, don't cache.
- If caching is enabled, check the slave lag of all configured slaves. Establish slave connections if none exist so far and lazy connections are used.
-
Send
SHOW SLAVE STATUSto all slaves. Do not wait for the first slave to reply before sending to the second slave. Clients often wait long for replies, thus we send out all requests in a burst before fetching in a second stage. -
Loop over all slaves. For every slave wait for its reply. Do not start
checking another slave before the currently waited for slave has replied.
Check for
Slave_IO_Running=YesandSlave_SQL_Running=Yes. If both conditions hold true, fetch the value ofSeconds_Behind_Master. In case of any errors or if conditions fail, set an error on the slave connection. Skip any such slave connection for the rest of connection filtering. -
Search for the maximum value of
Seconds_Behind_Masterfrom all slaves that passed the previous conditions. Subtract the value from the maximum age provided by the user with mysqlnd_ms_set_qos(). Use the result as a TTL. - The filtering may sort out all slaves. If so, the maximum age is used as TTL, because the maximum lag found equals zero. It is perfectly valid to sort out all slaves. In the following it is up to subsequent filter to decide what to do. The built-in load balancing filter will pick the master.
-
Inject the appropriate SQL hints to enable caching by
PECL/mysqlnd_qc. - Proceed with the connection filtering, e.g. apply load balancing rules to pick a slave.
-
PECL/mysqlnd_qcis loaded afterPECL/mysqlnd_msby PHP. Thus, it will see all query modifications ofPECL/mysqlnd_msand cache the query if instructed to do so.
The algorithm may seem expensive. SHOW SLAVE STATUS is a very
fast operation. Given a sufficient number of requests and cache hits per second the cost of
checking the slaves lag can easily outweigh the costs of the cache decision.
Suggestions on a better algorithm are always welcome.
Supported clusters
Any application using any kind of MySQL cluster is faced with the same tasks:
- Identify nodes capable of executing a given statement with the required service level
- Load balance requests within the list of candidates
- Automatic fail over within candidates, if needed
The plugin is optimized for fulfilling these tasks in the context of a classical asynchronous MySQL replication cluster consisting of a single master and many slaves (primary copy). When using classical, asynchronous MySQL replication all of the above listed tasks need to be mastered at the client side.
Other types of MySQL cluster may have lower requirements on the application side. For example, if all nodes in the cluster can answer read and write requests, no read-write splitting needs to be done (multi-master, update-all). If all nodes in the cluster are synchronous, they automatically provide the highest possible quality of service which makes choosing a node easier. In this case, the plugin may serve the application after some reconfiguration to disable certain features, such as built-in read-write splitting.
Note: Documentation focus
The documentation focusses describing the use of the plugin with classical asynchronous MySQL replication clusters (primary copy). Support for this kind of cluster has been the original development goal. Use of other clusters is briefly described below. Please note, that this is still work in progress.
Primary copy (MySQL Replication)
This is the primary use case of the plugin. Follow the hints given in the descriptions of each feature.
- Configure one master and one or more slaves. Server configuration details are given in the setup section.
- Use random load balancing policy together with the sticky flag.
- If you do not plan to use the service level API calls, add the master on write flag.
- Please, make yourself aware of the properties of automatic failover before adding a failover directive.
- Consider the use of trx_stickiness to execute transactions on the primary only. Please, read carefully how it works before you rely on it.
Example #1 Enabling the plugin (php.ini)
mysqlnd_ms.enable=1 mysqlnd_ms.config_file=/path/to/mysqlnd_ms_plugin.ini
Example #2 Basic plugin configuration (mysqlnd_ms_plugin.ini) for MySQL Replication
{
"myapp": {
"master": {
"master_1": {
"host": "localhost",
"socket": "\/tmp\/mysql57.sock"
}
},
"slave": {
"slave_0": {
"host": "127.0.0.1",
"port": 3308
},
"slave_1": {
"host": "192.168.2.28",
"port": 3306
}
},
"filters": {
"random": {
"sticky": "1"
}
}
}
}
Primary copy with multi primaries (MMM - MySQL Multi Master)
MySQL Replication allows you to create cluster topologies with multiple masters (primaries). Write-write conflicts are not handled by the replication system. This is no update anywhere setup. Thus, data must be partitioned manually and clients must redirected in accordance to the partitioning rules. The recommended setup is equal to the sharding setup below.
Manual sharding, possibly combined with primary copy and multiple primaries
Use SQL hints and the node group filter for clusters that use data partitioning but leave query redirection to the client. The example configuration shows a multi master setup with two shards.
Example #3 Multiple primaries - multi master (php.ini)
mysqlnd_ms.enable=1 mysqlnd_ms.config_file=/path/to/mysqlnd_ms_plugin.ini mysqlnd_ms.multi_master=1
Example #4 Primary copy with multiple primaries and paritioning
{
"myapp": {
"master": {
"master_1": {
"host": "localhost",
"socket": "\/tmp\/mysql57.sock"
}
"master_2": {
"host": "192.168.2.27",
"socket": "3306"
}
},
"slave": {
"slave_1": {
"host": "127.0.0.1",
"port": 3308
},
"slave_2": {
"host": "192.168.2.28",
"port": 3306
}
},
"filters": {
"node_groups": {
"Partition_A" : {
"master": ["master_1"],
"slave": ["slave_1"]
},
"Partition_B" : {
"master": ["master_2"],
"slave": ["slave_2"]
}
},
"roundrobin": []
}
}
}
The plugin can also be used with a loose collection of unrelated shards. For such a cluster, configure masters only and disable read write splitting. The nodes of such a cluster are called masters in the plugin configuration as they accept both reads and writes for their partition.
Using synchronous update everywhere clusters such as MySQL Cluster
MySQL Cluster is a synchronous cluster solution. All cluster nodes accept read and write requests. In the context of the plugin, all nodes shall be considered as masters.
Use the load balancing and fail over features only.
- Disable the plugins built-in read-write splitting.
- Configure masters only.
- Consider random once load balancing strategy, which is the plugins default. If random once is used, only masters are configured and no SQL hints are used to force using a certain node, no connection switches will happen for the duration of a web request. Thus, no special handling is required for transactions. The plugin will pick one master at the beginning of the PHP script and use it until the script terminates.
- Do not set the quality of service. All nodes have all the data. This automatically gives you the highest possible service quality (strong consistency).
- Do not enable client-side global transaction injection. It is neither required to help with server-side fail over nor to assist the quality of service filter choosing an appropriate node.
Disabling built-in read-write splitting.
-
Set
mysqlnd_ms.disable_rw_split=1 - Do not use SQL hints to enforce the use of slaves
Configure masters only.
-
Set
mysqlnd_ms.multi_master=1. - Do not configure any slaves.
-
Set
failover=loop_before_masterin the plugins configuration file to avoid warnings about the empty slave list and to make the failover logic loop over all configured masters before emitting an error. Please, note the warnings about automatic failover given in the previous sections.
Example #5 Multiple primaries - multi master (php.ini)
mysqlnd_ms.enable=1 mysqlnd_ms.config_file=/path/to/mysqlnd_ms_plugin.ini mysqlnd_ms.multi_master=1 mysqlnd_ms.disable_rw_split=1
Example #6 Synchronous update anywhere cluster
"myapp": {
"master": {
"master_1": {
"host": "localhost",
"socket": "\/tmp\/mysql57.sock"
},
"master_2": {
"host": "192.168.2.28",
"port": 3306
}
},
"slave": {
},
"filters": {
"roundrobin": {
}
},
"failover": {
"strategy": "loop_before_master",
"remember_failed": true
}
}
}
If running an update everywhere cluster that has no built-in partitioning to avoid hot spots and high collision rates, consider using the node groups filter to keep updates on a frequently accessed table on one of the nodes. This may help to reduce collision rates and thus improve performance.
XA/Distributed transactions
Note: Version requirement
XA related functions have been introduced in
PECL/mysqlnd_msversion 1.6.0-alpha.
Note: Early adaptors wanted
The feature is currently under development. There may be issues and/or feature limitations. Do not use in production environments, although early lab tests indicate reasonable quality.
Please, contact the development team if you are interested in this feature. We are looking for real life feedback to complement the feature.
Below is a list of some feature restrictions.
The feature is not yet compatible with the MySQL Fabric support . This limitation is soon to be lifted.
XA transaction identifier are currently restricted to numbers. This limitation will be lifted upon request, it is a simplification used during the initial implementation.
Note: MySQL server restrictions
The XA support by the MySQL server has some restrictions. Most noteably, the servers binary log may lack changes made by XA transactions in case of certain errors. Please, see the MySQL manual for details.
XA/Distributed transactions can spawn multiple MySQL servers.
Thus, they may seem like a perfect
tool for sharded MySQL clusters, for example, clusters managed with MySQL Fabric.
PECL/mysqlnd_ms hides most of the SQL commands
to control XA transactions and performs automatic administrative tasks in cases
of errors, to provide the user with a comprehensive API. Users should
setup the plugin carefully and be well aware of server restrictions prior
to using the feature.
Example #1 General pattern for XA transactions
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
/* BEGIN */
mysqlnd_ms_xa_begin($mysqli, 1 /* xa id */);
/* run queries on various servers */
$mysqli->query("UPDATE some_table SET col_a = 1");
...
/* COMMIT */
mysqlnd_ms_xa_commit($link, 1);
?>
XA transactions use the two-phase commit protocol. The two-phase commit protocol is a blocking protocol. During the first phase participating servers begin a transaction and the client carries out its work. This phase is followed by a second voting phase. During voting, the servers first make a firm promise that they are ready to commit the work even in case of their possible unexpected failure. Should a server crash in this phase, it will still recall the aborted transaction after recover and wait for the client to decide on whether it shall be committed or rolled back.
Should a client that has initiated a global transaction crash after all the participating servers gave their promise to be ready to commit, then the servers must wait for a decision. The servers are not allowed to unilaterally decide on the transaction.
A client crash or disconnect from a participant, a server crash or server error
during the fist phase of the protocol is uncritical. In most cases, the server
will forget about the XA transaction and its work is rolled back. Additionally,
the plugin tries to reach out to as many participants as it can to instruct
the server to roll back the work immediately. It is not possible to disable this implicit
rollback carried out by PECL/mysqlnd_ms in case of errors
during the first phase of the protocol. This design decision has been made to
keep the implementation simple.
An error during the second phase of the commit protocol can develop into a more severe situation. The servers will not forget about prepared but unfinished transactions in all cases. The plugin will not attempt to solve these cases immediately but waits for optional background garbage collection to ensure progress of the commit protocol. It is assumed that a solution will take significant time as it may include waiting for a participating server to recover from a crash. This time span may be longer than a developer and end user expects when trying to commit a global transaction with mysqlnd_ms_xa_commit(). Thus, the function returns with the unfinished global transaction still requiring attention. Please, be warned that at this point, it is not yet clear whether the global transaction will be committed or rolled back later on.
Errors during the second phase can be ignored, handled by yourself or solved by the build-int garbage collection logic. Ignoring them is not recommended as you may experience unfinished global transactions on your servers that block resources virtually indefinitely. Handling the errors requires knowing the participants, checking their state and issuing appropriate SQL commands on them. There are no user API calls to expose this very information. You will have to configure a state store and make the plugin record its actions in it to receive the desired facts.
Please, see the quickstart and related plugin configuration file settings for an example how to configure a state. In addition to configuring a state store, you have to setup some SQL tables. The table definitions are given in the description of the plugin configuration settings.
Setting up and configuring a state store is also a precondition for using the built-in garbage collection for XA transactions that fail during the second commit phase. Recording information about ongoing XA transactions is an unavoidable extra task. The extra task consists of updating the state store after each and every operation that changes the state of the global transaction itself (started, committed, rolled back, errors and aborts), the addition of participants (host, optionally user and password required to connect) and any changes to a participants state. Please note, depending on configuration and your security policies, these recordings may be considered sensitive. It is therefore recommended to restrict access to the state store. Unless the state store itself becomes overloaded, writing the state information may contribute noteworthy to the runtime but should overall be only a minor factor.
It is possible that the effort it takes to implement your own routines for handling
XA transactions that failed during the second commit phase exceeds the benefits
of using the XA feature of PECL/mysqlnd_ms in the first place.
Thus, the manual focussed on using the built-on garbage collection only.
Garbage collection can be triggered manually or automatically in the background. You may want to call mysqlnd_ms_xa_gc() immediately after a commit failure to attempt to solve any failed but still open global transactions as soon as possible. You may also decide to disable the automatic background garbage collection, implement your own rule set for invoking the built-in garbage collection and trigger it when desired.
By default the plugin will start the garbage collection with a certain probability
in the extensions internal RSHUTDOWN method. The request
shutdown is called after your script finished. Whether the garbage collection
will be triggered is determined by computing a random value between
1...1000 and comparing it with the configuration setting
probability
(default: 5). If the setting is
greater or equal to the random value, the garbage collection will be triggered.
Once started, the garbage collection acts upon up to
max_transactions_per_run (default: 100) global transactions
recorded. Records include successfully finished but also unfinished XA
transactions. Records for successful transactions are removed and unfinished
transactions are attempted to be solved. There are no statistics that help
you finding the right balance between keeping garbage collection runs short
by limiting the number of transactions considered per run and preventing the garbage
collection to fall behind, resulting in many records.
For each failed XA transaction the garbage collection makes
max_retries (default: 5) attempts to finish it. After that
PECL/mysqlnd_ms gives up. There are two possible reasons for this. Either
a participating server crashed and has not become accessible again within
max_retries invocations of the garbage collection, or there
is a situation that the built-in garbage collection cannot cope with. Likely, the
latter would be considered a bug. However, you can manually force more
garbage collection runs calling mysqlnd_ms_xa_gc() with the
appropriate parameter set. Should even those function runs fail to solve
the situation, then the problem must be solved by an operator.
The function mysqlnd_ms_get_stats() provides some statistics on how many XA transactions have been started, committed, failed or rolled back.
Installing/Configuring
Table of Contents
Requirements
PHP 5.3.6 or newer.
Some advanced functionality requires PHP 5.4.0 or newer.
The mysqlnd_ms replication and load balancing
plugin supports all PHP applications and all available PHP MySQL extensions
(mysqli,
mysql,
PDO_MYSQL).
The PHP MySQL extension must be configured to use
mysqlnd in order to be able
to use the mysqlnd_ms plugin for
mysqlnd.
Installation
This » PECL extension is not bundled with PHP.
Information for installing this PECL extension may be found in the manual chapter titled Installation of PECL extensions. Additional information such as new releases, downloads, source files, maintainer information, and a CHANGELOG, can be located here: » https://pecl.php.net/package/mysqlnd_ms
A DLL for this PECL extension is currently unavailable. See also the building on Windows section.
Runtime Configuration
The behaviour of these functions is affected by settings in php.ini.
| Name | Default | Changeable | Changelog |
|---|---|---|---|
| mysqlnd_ms.enable | 0 | PHP_INI_SYSTEM | |
| mysqlnd_ms.force_config_usage | 0 | PHP_INI_SYSTEM | |
| mysqlnd_ms.ini_file | "" | PHP_INI_SYSTEM | |
| mysqlnd_ms.config_file | "" | PHP_INI_SYSTEM | |
| mysqlnd_ms.collect_statistics | 0 | PHP_INI_SYSTEM | |
| mysqlnd_ms.multi_master | 0 | PHP_INI_SYSTEM | |
| mysqlnd_ms.disable_rw_split | 0 | PHP_INI_SYSTEM |
Here's a short explanation of the configuration directives.
-
mysqlnd_ms.enableinteger -
Enables or disables the plugin. If disabled, the extension will not plug into mysqlnd to proxy internal mysqlnd C API calls.
-
mysqlnd_ms.force_config_usageinteger -
If enabled, the plugin checks if the host (server) parameters value of any MySQL connection attempt, matches a section name from the plugin configuration file. If not, the connection attempt is blocked.
This setting is not only useful to restrict PHP to certain servers but also to debug configuration file problems. The configuration file validity is checked at two different stages. The first check is performed when PHP begins to handle a web request. At this point the plugin reads and decodes the configuration file. Errors thrown at this early stage in an extensions life cycle may not be shown properly to the user. Thus, the plugin buffers the errors, if any, and additionally displays them when establishing a connection to MySQL. By default a buffered startup error will emit an error of type
E_WARNING. Ifforce_config_usageis set, the error type used isE_RECOVERABLE_ERROR.Please, see also configuration file debugging notes.
-
mysqlnd_ms.ini_filestring -
Plugin specific configuration file. This setting has been renamed to
mysqlnd_ms.config_filein version 1.4.0. -
mysqlnd_ms.config_filestring -
Plugin specific configuration file. This setting superseeds
mysqlnd_ms.ini_filesince 1.4.0. -
mysqlnd_ms.collect_statisticsinteger -
Enables or disables the collection of statistics. The collection of statistics is disabled by default for performance reasons. Statistics are returned by the function mysqlnd_ms_get_stats().
-
mysqlnd_ms.multi_masterinteger -
Enables or disables support of MySQL multi master replication setups. Please, see also supported clusters.
-
mysqlnd_ms.disable_rw_splitinteger -
Enables or disables built-in read write splitting.
Controls whether load balancing and lazy connection functionality can be used independently of read write splitting. If read write splitting is disabled, only servers from the master list will be used for statement execution. All configured slave servers will be ignored.
The SQL hint
MYSQLND_MS_USE_SLAVEwill not be recognized. If found, the statement will be redirected to a master.Disabling read write splitting impacts the return value of mysqlnd_ms_query_is_select(). The function will no longer propose query execution on slave servers.
Note: Multiple master servers
Setting
mysqlnd_ms.multi_master=1allows the plugin to use multiple master servers, instead of only the first master server of the master list.Please, see also supported clusters.
Plugin configuration file (>=1.1.x)
The following documentation applies to PECL/mysqlnd_ms >= 1.1.0-beta. It is not valid for prior versions. For documentation covering earlier versions, see the configuration documentation for mysqlnd_ms 1.0.x and below.
Introduction
Note: Changelog: Feature was added in PECL/mysqlnd_ms 1.1.0-beta
The below description applies to PECL/mysqlnd_ms >= 1.1.0-beta. It is not valid for prior versions.
The plugin uses its own configuration file. The configuration file holds information about the MySQL replication master server, the MySQL replication slave servers, the server pick (load balancing) policy, the failover strategy, and the use of lazy connections.
The plugin loads its configuration file at the beginning of a web request. It is then cached in memory and used for the duration of the web request. This way, there is no need to restart PHP after deploying the configuration file. Configuration file changes will become active almost instantly.
The PHP configuration directive
mysqlnd_ms.config_file
is used to set the plugins configuration file. Please note, that
the PHP configuration directive may not be evaluated for every web request.
Therefore, changing the plugins configuration file name or location may
require a PHP restart. However, no restart is required to read changes if
an already existing plugin configuration file is updated.
Using and parsing JSON is efficient, and using JSON makes it easier to express hierarchical data structures than the standard php.ini format.
Example #1 Converting a PHP array (hash) into JSON format
Or alternatively, a developer may be more familiar with the PHP array syntax, and prefer it. This example demonstrates how a developer might convert a PHP array to JSON.
<?php
$config = array(
"myapp" => array(
"master" => array(
"master_0" => array(
"host" => "localhost",
"socket" => "/tmp/mysql.sock",
),
),
"slave" => array(),
),
);
file_put_contents("mysqlnd_ms.ini", json_encode($config, JSON_PRETTY_PRINT));
printf("mysqlnd_ms.ini file created...\n");
printf("Dumping file contents...\n");
printf("%s\n", str_repeat("-", 80));
echo file_get_contents("mysqlnd_ms.ini");
printf("\n%s\n", str_repeat("-", 80));
?>
The above example will output:
mysqlnd_ms.ini file created...
Dumping file contents...
--------------------------------------------------------------------------------
{
"myapp": {
"master": {
"master_0": {
"host": "localhost",
"socket": "\/tmp\/mysql.sock"
}
},
"slave": [
]
}
}
--------------------------------------------------------------------------------
A plugin configuration file consists of one or more sections. Sections are represented by the top-level object properties of the object encoded in the JSON file. Sections could also be called configuration names.
Applications reference sections by their name. Applications use section names as the host (server) parameter to the various connect methods of the mysqli, mysql and PDO_MYSQL extensions. Upon connect, the mysqlnd plugin compares the hostname with all of the section names from the plugin configuration file. If the hostname and section name match, then the plugin will load the settings for that section.
Example #2 Using section names example
{
"myapp": {
"master": {
"master_0": {
"host": "localhost"
}
},
"slave": {
"slave_0": {
"host": "192.168.2.27"
},
"slave_1": {
"host": "192.168.2.27",
"port": 3306
}
}
},
"localhost": {
"master": [
{
"host": "localhost",
"socket": "\/path\/to\/mysql.sock"
}
],
"slave": [
{
"host": "192.168.3.24",
"port": "3305"
},
{
"host": "192.168.3.65",
"port": "3309"
}
]
}
}
<?php
/* All of the following connections will be load balanced */
$mysqli = new mysqli("myapp", "username", "password", "database");
$pdo = new PDO('mysql:host=myapp;dbname=database', 'username', 'password');
$mysql = mysql_connect("myapp", "username", "password");
$mysqli = new mysqli("localhost", "username", "password", "database");
?>
Section names are strings. It is valid to use a section name such as
192.168.2.1, 127.0.0.1 or
localhost. If, for example, an application
connects to localhost and a plugin
configuration section localhost exists, the
semantics of the connect operation are changed. The application will
no longer only use the MySQL server running on the host
localhost, but the plugin will start to load balance
MySQL queries following the rules from the localhost
configuration section. This way you can load balance queries from
an application without changing the applications source code.
Please keep in mind, that such a configuration may not contribute
to overall readability of your applications source code. Using section names
that can be mixed up with host names should be seen as a last resort.
Each configuration section contains, at a minimum, a list of master servers
and a list of slave servers. The master list is configured with the keyword
master, while the slave list is configured with the
slave keyword. Failing to provide a slave list will result
in a fatal E_ERROR level error, although a slave list
may be empty. It is possible to allow no slaves. However, this is only recommended
with synchronous clusters, please see also
supported clusters.
The main part of the documentation focusses on the use
of asynchronous MySQL replication clusters.
The master and slave server lists can be optionally indexed by symbolic names for the servers they describe. Alternatively, an array of descriptions for slave and master servers may be used.
Example #3 List of anonymous slaves
"slave": [
{
"host": "192.168.3.24",
"port": "3305"
},
{
"host": "192.168.3.65",
"port": "3309"
}
]
An anonymous server list is encoded by the JSON array type.
Optionally, symbolic names may be used for indexing the slave or master servers
of a server list, and done so using the JSON object type.
Example #4 Master list using symbolic names
"master": {
"master_0": {
"host": "localhost"
}
}
It is recommended to index the server lists with symbolic server names. The alias names will be shown in error messages.
The order of servers is preserved and taken into account by mysqlnd_ms.
If, for example, you configure round robin load balancing strategy, the
first SELECT statement will be executed on the
slave that appears first in the slave server list.
A configured server can be described with the host,
port, socket, db,
user, password and connect_flags.
It is mandatory to set the database server host using the host
keyword. All other settings are optional.
Example #5 Keywords to configure a server
{
"myapp": {
"master": {
"master_0": {
"host": "db_server_host",
"port": "db_server_port",
"socket": "db_server_socket",
"db": "database_resp_schema",
"user": "user",
"password": "password",
"connect_flags": 0
}
},
"slave": {
"slave_0": {
"host": "db_server_host",
"port": "db_server_port",
"socket": "db_server_socket"
}
}
}
}
If a setting is omitted, the plugin will use the value provided by the user API call used to open a connection. Please, see the using section names example above.
The configuration file format has been changed in version 1.1.0-beta to allow for
chained filters. Filters are responsible for filtering the configured list of
servers to identify a server for execution of a given statement.
Filters are configured with the filter keyword. Filters
are executed by mysqlnd_ms in the order of their appearance.
Defining filters is optional. A configuration section in the plugins
configuration file does not need to have a filters entry.
Filters replace the
pick[]
setting from prior versions. The new random and
roundrobin provide the same functionality.
Example #6 New roundrobin filter, old functionality
{
"myapp": {
"master": {
"master_0": {
"host": "localhost"
}
},
"slave": {
"slave_0": {
"host": "192.168.78.136",
"port": "3306"
},
"slave_1": {
"host": "192.168.78.137",
"port": "3306"
}
},
"filters": {
"roundrobin": [
]
}
}
}
The function
mysqlnd_ms_set_user_pick_server()
has been removed. Setting a callback is now done with the user
filter. Some filters accept parameters. The user filter
requires and accepts a mandatory callback parameter
to set the callback previously set through the function mysqlnd_ms_set_user_pick_server().
Example #7 The user filter replaces mysqlnd_ms_set_user_pick_server()
"filters": {
"user": {
"callback": "pick_server"
}
}
The validity of the configuration file is checked both when reading the configuration file and later when establishing a connection. The configuration file is read during PHP request startup. At this early stage a PHP extension may not display error messages properly. In the worst case, no error is shown and a connection attempt fails without an adequate error message. This problem has been cured in version 1.5.0.
Example #8 Common error message in case of configuration file issues (upto version 1.5.0)
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
?>
The above example will output:
Warning: mysqli::mysqli(): (mysqlnd_ms) (mysqlnd_ms) Failed to parse config file [s1.json]. Please, verify the JSON in Command line code Warning: mysqli::mysqli(): (HY000/2002): php_network_getaddresses: getaddrinfo failed: Name or service not known in Command line code on line 1 Warning: mysqli::query(): Couldn't fetch mysqli in Command line code on line 1 Fatal error: Call to a member function fetch_assoc() on a non-object in Command line code on line 1
Since version 1.5.0 startup errors are additionally buffered and emitted when
a connection attempt is made. Use the configuration directive
mysqlnd_ms.force_config_usage
to set the error type used to display buffered errors. By default an error
of type E_WARNING will be emitted.
Example #9 Improved configuration file validation since 1.5.0
<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
?>
The above example will output:
Warning: mysqli::mysqli(): (mysqlnd_ms) (mysqlnd_ms) Failed to parse config file [s1.json]. Please, verify the JSON in Command line code on line 1
It can be useful to set mysqlnd_ms.force_config_usage = 1
when debugging potential configuration file errors. This will not only turn the
type of buffered startup errors into E_RECOVERABLE_ERROR but also
help detecting misspelled section names.
Example #10 Possibly more precise error due to mysqlnd_ms.force_config_usage=1
mysqlnd_ms.force_config_usage=1
<?php
$mysqli = new mysqli("invalid_section", "username", "password", "database");
?>
The above example will output:
Warning: mysqli::mysqli(): (mysqlnd_ms) Exclusive usage of configuration enforced but did not find the correct INI file section (invalid_section) in Command line code on line 1 line 1
Configuration Directives
Here is a short explanation of the configuration directives that can be used.
-
masterarray or object -
List of MySQL replication master servers. The list of either of the
JSON type arrayto declare an anonymous list of servers or of theJSON type object. Please, see above for examples.Setting at least one master server is mandatory. The plugin will issue an error of type
E_ERRORif the user has failed to provide a master server list for a configuration section. The fatal error may read(mysqlnd_ms) Section [master] doesn't exist for host [name_of_a_config_section] in %s on line %d.A server is described with the
host,port,socket,db,user,passwordandconnect_flags. It is mandatory to provide at a value forhost. If any of the other values is not given, it will be taken from the user API connect call, please, see also: using section names example.Table of server configuration keywords.
Keyword Description Version hostDatabase server host. This is a mandatory setting. Failing to provide, will cause an error of type
E_RECOVERABLE_ERRORwhen the plugin tries to connect to the server. The error message may read(mysqlnd_ms) Cannot find [host] in [%s] section in config in %s on line %d.Since 1.1.0. portDatabase server TCP/IP port.
Since 1.1.0. socketDatabase server Unix domain socket.
Since 1.1.0. dbDatabase (schemata).
Since 1.1.0. userMySQL database user.
Since 1.1.0. passwordMySQL database user password.
Since 1.1.0. connect_flagsConnection flags.
Since 1.1.0. The plugin supports using only one master server. An experimental setting exists to enable multi-master support. The details are not documented. The setting is meant for development only.
-
slavearray or object -
List of one or more MySQL replication slave servers. The syntax is identical to setting master servers, please, see
masterabove for details.The plugin supports using one or more slave servers.
Setting a list of slave servers is mandatory. The plugin will report an error of the type
E_ERRORifslaveis not given for a configuration section. The fatal error message may read(mysqlnd_ms) Section [slave] doesn't exist for host [%s] in %s on line %d. Note, that it is valid to use an empty slave server list. The error has been introduced to prevent accidentally setting no slaves by forgetting about theslavesetting. A master-only setup is still possible using an empty slave server list.If an empty slave list is configured and an attempt is made to execute a statement on a slave the plugin may emit a warning like
mysqlnd_ms) Couldn't find the appropriate slave connection. 0 slaves to choose from.upon statement execution. It is possible that another warning follows such as(mysqlnd_ms) No connection selected by the last filter. -
global_transaction_id_injectionarray or object -
Global transaction identifier configuration related to both the use of the server built-in global transaction ID feature and the client-side emulation.
Keyword Description Version fetch_last_gtidSQL statement for accessing the latest global transaction identifier. The SQL statement is run if the plugin needs to know the most recent global transaction identifier. This can be the case, for example, when checking MySQL Replication slave status. Also used with mysqlnd_ms_get_last_gtid().
Since 1.2.0. check_for_gtidSQL statement for checking if a replica has replicated all transactions up to and including ones searched for. The SQL statement is run when searching for replicas which can offer a higher level of consistency than eventual consistency. The statement must contain a placeholder
#GTIDwhich is to be replaced with the global transaction identifier searched for by the plugin. Please, check the quickstart for examples.Since 1.2.0. report_errorsWhether to emit an error of type warning if an issue occurs while executing any of the configured SQL statements.
Since 1.2.0. on_commitClient-side global transaction ID emulation only. SQL statement to run when a transaction finished to update the global transaction identifier sequence number on the master. Please, see the quickstart for examples.
Since 1.2.0. wait_for_gtid_timeoutInstructs the plugin to wait up to
wait_for_gtid_timeoutseconds for a slave to catch up when searching for slaves that can deliver session consistency. The setting limits the time spend for polling the slave status. If polling the status takes very long, the total clock time spend waiting may exceedwait_for_gtid_timeout. The plugin callssleep(1)to sleep one second between each two polls.The setting can be used both with the plugins client-side emulation and the server-side global transaction identifier feature of MySQL 5.6.
Waiting for a slave to replicate a certain GTID needed for session consistency also means throttling the client. By throttling the client the write load on the master is reduced indirectly. A primary copy based replication system, such as MySQL Replication, is given more time to reach a consistent state. This can be desired, for example, to increase the number of data copies for high availability considerations or to prevent the master from being overloaded.
Since 1.4.0. -
fabricobject -
MySQL Fabric related settings. If the plugin is used together with MySQL Fabric, then the plugins configuration file no longer contains lists of MySQL servers. Instead, the plugin will ask MySQL Fabric which list of servers to use to perform a certain task.
A minimum plugin configuration for use with MySQL Fabric contains a list of one or more MySQL Fabric hosts that the plugin can query. If more than one MySQL Fabric host is configured, the plugin will use a roundrobin strategy to choose among them. Other strategies are currently not available.
Example #11 Minimum pluging configuration for use with MySQL Fabric
{ "myapp": { "fabric": { "hosts": [ { "host" : "127.0.0.1", "port" : 8080 } ] } } }Each MySQL Fabric host is described using a JSON object with the following members.
Keyword Description Version hostHost name of the MySQL Fabric host.
Since 1.6.0. portThe TCP/IP port on which the MySQL Fabric host listens for remote procedure calls sent by clients such as the plugin.
Since 1.6.0. The plugin is using PHP streams to communicate with MySQL Fabric through XML RPC over HTTP. By default no timeouts are set for the network communication. Thus, the plugin defaults to PHP stream default timeouts. Those defaults are out of control of the plugin itself.
An optional timeout value can be set to overrule the PHP streams default timeout setting. Setting the timeout in the plugins configuration file has the same effect as setting a timeout for a PHP user space HTTP connection established through PHP streams.
The plugins Fabric timeout value unit is seconds. The allowed value range is from 0 to 65535. The setting exists since version 1.6.
Example #12 Optional timeout for communication with Fabric
{ "myapp": { "fabric": { "hosts": [ { "host" : "127.0.0.1", "port" : 8080 } ], "timeout": 2 } } }Transaction stickiness and MySQL Fabric logic can collide. The stickiness option disables switching between servers for the duration of a transaction. When using Fabric and sharding the user may (erroneously) start a local transaction on one share and then attempt to switch to a different shard using either mysqlnd_ms_fabric_select_shard() or mysqlnd_ms_fabric_select_global(). In this case, the plugin will not reject the request to switch servers in the middle of a transaction but allow the user to switch to another server regardless of the transaction stickiness setting used. It is clearly a user error to write such code.
If transaction stickiness is enabled and you would like to get an error of type warning when calling mysqlnd_ms_fabric_select_shard() or mysqlnd_ms_fabric_select_global(), set the boolean flag
trx_warn_server_list_changes.Example #13 Warnings about the violation of transaction boundaries
{ "myapp": { "fabric": { "hosts": [ { "host" : "127.0.0.1", "port" : 8080 } ], "trx_warn_serverlist_changes": 1 }, "trx_stickiness": "on" } }<?php
$link = new mysqli("myapp", "root", "", "test");
/*
For the demo the call may fail.
Failed or not we get into the state
needed for the example.
*/
@mysqlnd_ms_fabric_select_global($link, 1);
$link->begin_transaction();
@$link->query("DROP TABLE IF EXISTS test");
/*
Switching servers/shards is a mistake due to open
local transaction!
*/
mysqlnd_ms_select_global($link, 1);
?>The above example will output:
PHP Warning: mysqlnd_ms_fabric_select_global(): (mysqlnd_ms) Fabric server exchange in the middle of a transaction in %s on line %d
Please, consider the feature experimental. Changes to syntax and semantics may happen.
-
filtersobject -
List of filters. A filter is responsible to filter the list of available servers for executing a given statement. Filters can be chained. The
randomandroundrobinfilter replace thepick[]directive used in prior version to select a load balancing policy. Theuserfilter replaces the mysqlnd_ms_set_user_pick_server() function.Filters may accept parameters to refine their actions.
If no load balancing policy is set, the plugin will default to
random_once. Therandom_oncepolicy picks a random slave server when running the first read-only statement. The slave server will be used for all read-only statements until the PHP script execution ends. No load balancing policy is set and thus, defaulting takes place, if neither therandomnor theroundrobinare part of a configuration section.If a filter chain is configured so that a filter which output no more than once server is used as input for a filter which should be given more than one server as input, the plugin may emit a warning upon opening a connection. The warning may read:
(mysqlnd_ms) Error while creating filter '%s' . Non-multi filter '%s' already created. Stopping in %s on line %d. Furthermore, an error of the error code2000, the sql stateHY000and an error message similar to the warning may be set on the connection handle.Example #14 Invalid filter sequence
{ "myapp": { "master": { "master_0": { "host": "localhost" } }, "slave": { "slave_0": { "host": "192.168.78.136", "port": "3306" } }, "filters": [ "roundrobin", "random" ] } }<?php
$link = new mysqli("myapp", "root", "", "test");
printf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error());
$link->query("SELECT 1 FROM DUAL");
?>The above example will output:
PHP Warning: mysqli::mysqli(): (HY000/2000): (mysqlnd_ms) Error while creating filter 'random' . Non-multi filter 'roundrobin' already created. Stopping in filter_warning.php on line 1 [2000] (mysqlnd_ms) Error while creating filter 'random' . Non-multi filter 'roundrobin' already created. Stopping PHP Warning: mysqli::query(): Couldn't fetch mysqli in filter_warning.php on line 3
-
Filter:
randomobject -
The
randomfilter features the random and random once load balancing policies, set through thepick[]directive in older versions.The random policy will pick a random server whenever a read-only statement is to be executed. The random once strategy picks a random slave server once and continues using the slave for the rest of the PHP web request. Random once is a default, if load balancing is not configured through a filter.
If the
randomfilter is not given any arguments, it stands for random load balancing policy.Example #15 Random load balancing with
randomfilter{ "myapp": { "master": { "master_0": { "host": "localhost" } }, "slave": { "slave_0": { "host": "192.168.78.136", "port": "3306" }, "slave_1": { "host": "192.168.78.137", "port": "3306" } }, "filters": [ "random" ] } }Optionally, the
stickyargument can be passed to the filter. If the parameterstickyis set to the string1, the filter follows the random once load balancing strategy.Example #16 Random once load balancing with
randomfilter{ "filters": { "random": { "sticky": "1" } } }Both the
randomandroundrobinfilters support setting a priority, a weight for a server, since PECL/mysqlnd_ms 1.4.0. If theweightargument is passed to the filter, it must assign a weight for all servers. Servers must be given an alias name in theslaverespectivelymasterserver lists. The alias must be used to reference servers for assigning a priority withweight.Example #17 Referencing error
[E_RECOVERABLE_ERROR] mysqli_real_connect(): (mysqlnd_ms) Unknown server 'slave3' in 'random' filter configuration. Stopping in %s on line %d
Using a wrong alias name with
weightmay result in an error similar to the shown above.If
weightis omitted, the default weight of all servers is one.Example #18 Assigning a
weightfor load balancing{ "myapp": { "master": { "master1":{ "host":"localhost", "socket":"\/var\/run\/mysql\/mysql.sock" } }, "slave": { "slave1": { "host":"192.168.2.28", "port":3306 }, "slave2": { "host":"192.168.2.29", "port":3306 }, "slave3": { "host":"192.0.43.10", "port":3306 }, }, "filters": { "random": { "weights": { "slave1":8, "slave2":4, "slave3":1, "master1":1 } } } } }At the average a server assigned a weight of two will be selected twice as often as a server assigned a weight of one. Different weights can be assigned to reflect differently sized machines, to prefer co-located slaves which have a low network latency or, to configure a standby failover server. In the latter case, you may want to assign the standby server a very low weight in relation to the other servers. For example, given the configuration above
slave3will get only some eight percent of the requests in the average. As long asslave1andslave2are running, it will be used sparsely, similar to a standby failover server. Upon failure ofslave1andslave2, the usage ofslave3increases. Please, check the notes on failover before usingweightthis way.Valid weight values range from 1 to 65535.
Unknown arguments are ignored by the filter. No warning or error is given.
The filter expects one or more servers as input. Outputs one server. A filter sequence such as
random,roundrobinmay cause a warning and an error message to be set on the connection handle when executing a statement.List of filter arguments.
Keyword Description Version stickyEnables or disabled random once load balancing policy. See above.
Since 1.2.0. weightAssigns a load balancing weight/priority to a server. Please, see above for a description.
Since 1.4.0. -
Filter:
roundrobinobject -
If using the
roundrobinfilter, the plugin iterates over the list of configured slave servers to pick a server for statement execution. If the plugin reaches the end of the list, it wraps around to the beginning of the list and picks the first configured slave server.Example #19
roundrobinfilter{ "myapp": { "master": { "master_0": { "host": "localhost" } }, "slave": { "slave_0": { "host": "192.168.78.136", "port": "3306" } }, "filters": [ "roundrobin" ] } }Expects one or more servers as input. Outputs one server. A filter sequence such as
roundrobin,randommay cause a warning and an error message to be set on the connection handle when executing a statement.List of filter arguments.
Keyword Description Version weightAssigns a load balancing weight/priority to a server. Please, find a description above.
Since 1.4.0. -
Filter:
userobject -
The
userreplaces mysqlnd_ms_set_user_pick_server() function, which was removed in 1.1.0-beta. The filter sets a callback for user-defined read/write splitting and server selection.The plugins built-in read/write query split mechanism decisions can be overwritten in two ways. The easiest way is to prepend a query string with the SQL hints
MYSQLND_MS_MASTER_SWITCH,MYSQLND_MS_SLAVE_SWITCHorMYSQLND_MS_LAST_USED_SWITCH. Using SQL hints one can control, for example, whether a query shall be send to the MySQL replication master server or one of the slave servers. By help of SQL hints it is not possible to pick a certain slave server for query execution.Full control on server selection can be gained using a callback function. Use of a callback is recommended to expert users only because the callback has to cover all cases otherwise handled by the plugin.
The plugin will invoke the callback function for selecting a server from the lists of configured master and slave servers. The callback function inspects the query to run and picks a server for query execution by returning the hosts URI, as found in the master and slave list.
If the lazy connections are enabled and the callback chooses a slave server for which no connection has been established so far and establishing the connection to the slave fails, the plugin will return an error upon the next action on the failed connection, for example, when running a query. It is the responsibility of the application developer to handle the error. For example, the application can re-run the query to trigger a new server selection and callback invocation. If so, the callback must make sure to select a different slave, or check slave availability, before returning to the plugin to prevent an endless loop.
Example #20 Setting a callback
{ "myapp": { "master": { "master_0": { "host": "localhost" } }, "slave": { "slave_0": { "host": "192.168.78.136", "port": "3306" } }, "filters": { "user": { "callback": "pick_server" } } } }The callback is supposed to return a host to run the query on. The host URI is to be taken from the master and slave connection lists passed to the callback function. If callback returns a value neither found in the master nor in the slave connection lists the plugin will emit an error of the type
E_RECOVERABLE_ERRORThe error may read like(mysqlnd_ms) User filter callback has returned an unknown server. The server 'server that is not in master or slave list' can neither be found in the master list nor in the slave list. If the application catches the error to ignore it, follow up errors may be set on the connection handle, for example,(mysqlnd_ms) No connection selected by the last filterwith the error code2000and the sqlstateHY000. Furthermore a warning may be emitted.Referencing a non-existing function as a callback will result in any error of the type
E_RECOVERABLE_ERRORwhenever the plugin tries to callback function. The error message may reads like:(mysqlnd_ms) Specified callback (pick_server) is not a valid callback. If the application catches the error to ignore it, follow up errors may be set on the connection handle, for example,(mysqlnd_ms) Specified callback (pick_server) is not a valid callbackwith the error code2000and the sqlstateHY000. Furthermore a warning may be emitted.The following parameters are passed from the plugin to the callback.
Parameter Description Version connected_hostURI of the currently connected database server.
Since 1.1.0. queryQuery string of the statement for which a server needs to be picked.
Since 1.1.0. mastersList of master servers to choose from. Note, that the list of master servers may not be identical to the list of configured master servers if the filter is not the first in the filter chain. Previously run filters may have reduced the master list already.
Since 1.1.0. slavesList of slave servers to choose from. Note, that the list of slave servers may not be identical to the list of configured slave servers if the filter is not the first in the filter chain. Previously run filters may have reduced the slave list already.
Since 1.1.0. last_used_connectionURI of the server of the connection used to execute the previous statement on.
Since 1.1.0. in_transactionBoolean flag indicating whether the statement is part of an open transaction. If autocommit mode is turned off, this will be set to
TRUE. Otherwise it is set toFALSE.Transaction detection is based on monitoring the mysqlnd library call
set_autocommit. Monitoring is not possible before PHP 5.4.0. Please, see connection pooling and switching concepts discussion for further details.Since 1.1.0. Example #21 Using a callback
{ "myapp": { "master": { "master_0": { "host": "localhost" } }, "slave": { "slave_0": { "host": "192.168.2.27", "port": "3306" }, "slave_1": { "host": "192.168.78.136", "port": "3306" } }, "filters": { "user": { "callback": "pick_server" } } } }<?php
function pick_server($connected, $query, $masters, $slaves, $last_used_connection, $in_transaction)
{
static $slave_idx = 0;
static $num_slaves = NULL;
if (is_null($num_slaves))
$num_slaves = count($slaves);
/* default: fallback to the plugins build-in logic */
$ret = NULL;
printf("User has connected to '%s'...\n", $connected);
printf("... deciding where to run '%s'\n", $query);
$where = mysqlnd_ms_query_is_select($query);
switch ($where)
{
case MYSQLND_MS_QUERY_USE_MASTER:
printf("... using master\n");
$ret = $masters[0];
break;
case MYSQLND_MS_QUERY_USE_SLAVE:
/* SELECT or SQL hint for using slave */
if (stristr($query, "FROM table_on_slave_a_only"))
{
/* a table which is only on the first configured slave */
printf("... access to table available only on slave A detected\n");
$ret = $slaves[0];
}
else
{
/* round robin */
printf("... some read-only query for a slave\n");
$ret = $slaves[$slave_idx++ % $num_slaves];
}
break;
case MYSQLND_MS_QUERY_LAST_USED:
printf("... using last used server\n");
$ret = $last_used_connection;
break;
}
printf("... ret = '%s'\n", $ret);
return $ret;
}
$mysqli = new mysqli("myapp", "root", "", "test");
if (!($res = $mysqli->query("SELECT 1 FROM DUAL")))
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
else
$res->close();
if (!($res = $mysqli->query("SELECT 2 FROM DUAL")))
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
else
$res->close();
if (!($res = $mysqli->query("SELECT * FROM table_on_slave_a_only")))
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
else
$res->close();
$mysqli->close();
?>The above example will output:
User has connected to 'myapp'... ... deciding where to run 'SELECT 1 FROM DUAL' ... some read-only query for a slave ... ret = 'tcp://192.168.2.27:3306' User has connected to 'myapp'... ... deciding where to run 'SELECT 2 FROM DUAL' ... some read-only query for a slave ... ret = 'tcp://192.168.78.136:3306' User has connected to 'myapp'... ... deciding where to run 'SELECT * FROM table_on_slave_a_only' ... access to table available only on slave A detected ... ret = 'tcp://192.168.2.27:3306'
-
Filter:
user_multiobject -
The
user_multidiffers from theuseronly in one aspect. Otherwise, their syntax is identical. Theuserfilter must pick and return exactly one node for statement execution. A filter chain usually ends with a filter that emits only one node. The filter chain shall reduce the list of candidates for statement execution down to one. This, only one node left, is the case after theuserfilter has been run.The
user_multifilter is a multi filter. It returns a list of slave and a list of master servers. This list needs further filtering to identify exactly one node for statement execution. A multi filter is typically placed at the top of the filter chain. Thequality_of_servicefilter is another example of a multi filter.The return value of the callback set for
user_multimust be an array with two elements. The first element holds a list of selected master servers. The second element contains a list of selected slave servers. The lists shall contain the keys of the slave and master servers as found in the slave and master lists passed to the callback. The below example returns random master and slave lists extracted from the functions input.Example #22 Returning random masters and slaves
<?php
function pick_server($connected, $query, $masters, $slaves, $last_used_connection, $in_transaction)
{
$picked_masters = array()
foreach ($masters as $key => $value) {
if (mt_rand(0, 2) > 1)
$picked_masters[] = $key;
}
$picked_slaves = array()
foreach ($slaves as $key => $value) {
if (mt_rand(0, 2) > 1)
$picked_slaves[] = $key;
}
return array($picked_masters, $picked_slaves);
}
?>The plugin will issue an error of type
E_RECOVERABLEif the callback fails to return a server list. The error may read(mysqlnd_ms) User multi filter callback has not returned a list of servers to use. The callback must return an array in %s on line %d. In case the server list is not empty but has invalid servers key/ids in it, an error of typeE_RECOVERABLEwill the thrown with an error message like(mysqlnd_ms) User multi filter callback has returned an invalid list of servers to use. Server id is negative in %s on line %d, or similar.Whether an error is emitted in case of an empty slave or master list depends on the configuration. If an empty master list is returned for a write operation, it is likely that the plugin will emit a warning that may read
(mysqlnd_ms) Couldn't find the appropriate master connection. 0 masters to choose from. Something is wrong in %s on line %d. Typically a follow up error of typeE_ERRORwill happen. In case of a read operation and an empty slave list the behavior depends on the fail over configuration. If fail over to master is enabled, no error should appear. If fail over to master is deactivated the plugin will emit a warning that may read(mysqlnd_ms) Couldn't find the appropriate slave connection. 0 slaves to choose from. Something is wrong in %s on line %d. -
Filter:
node_groupsobject -
The
node_groupsfilter lets you group cluster nodes and query selected groups, for example, to support data partitioning. Data partitioning can be required for manual sharding, primary copy based clusters running multiple masters, or to avoid hot spots in update everywhere clusters that have no built-in partitioning. The filter is a multi filter which returns zero, one or multiple of its input servers. Thus, it must be followed by other filters to reduce the number of candidates down to one for statement execution.Keyword Description Version user defined node group nameOne or more node groups must be defined. A node group can have an arbitrary user defined name. The name is used in combination with a SQL hint to restrict query execution to the nodes listed for the node group. To run a query on any of the servers of a node group, the query must begin with the SQL hint
/*user defined node group name*/. Please note, no white space is allowed arounduser defined node group name. Becauseuser defined node group nameis used as-is as part of a SQL hint, you should choose the name that is compliant with the SQL language.Each node group entry must contain a list of
masterservers. Additionalslaveservers are allowed. Failing to provide a list ofmasterfor a node groupname_of_groupmay cause an error of typeE_RECOVERABLE_ERRORlike(mysqlnd_ms) No masters configured in node group 'name_of_group' for 'node_groups' filter.The list of master and slave servers must reference corresponding entries in the global master respectively slave server list. Referencing an unknown server in either of the both server lists may cause an
E_RECOVERABLE_ERRORerror like(mysqlnd_ms) Unknown master 'server_alias_name' (section 'name_of_group') in 'node_groups' filter configuration.Example #23 Manual partitioning
{ "myapp": { "master": { "master_0": { "host": "localhost", "socket": "\/tmp\/mysql.sock" } }, "slave": { "slave_0": { "host": "192.168.2.28", "port": 3306 }, "slave_1": { "host": "127.0.0.1", "port": 3311 } }, "filters": { "node_groups": { "Partition_A" : { "master": ["master_0"], "slave": ["slave_0"] } }, "roundrobin": [] } } }Please note, if a filter chain generates an empty slave list and the PHP configuration directive
mysqlnd_ms.multi_master=0is used, the plugin may emit a warning.Since 1.5.0. -
Filter:
quality_of_serviceobject -
The
quality_of_serviceidentifies cluster nodes capable of delivering a certain quality of service. It is a multi filter which returns zero, one or multiple of its input servers. Thus, it must be followed by other filters to reduce the number of candidates down to one for statement execution.The
quality_of_servicefilter has been introduced in 1.2.0-alpha. In the 1.2 series the filters focus is on the consistency aspect of service quality. Different types of clusters offer different default data consistencies. For example, an asynchronous MySQL replication slave offers eventual consistency. The slave may not be able to deliver requested data because it has not replicated the write, it may serve stale database because its lagging behind or it may serve current information. Often, this is acceptable. In some cases higher consistency levels are needed for the application to work correct. In those cases, thequality_of_servicecan filter out cluster nodes which cannot deliver the necessary quality of service.The
quality_of_servicefilter can be replaced or created at runtime. A successful call to mysqlnd_ms_set_qos() removes all existingqosfilter entries from the filter list and installs a new one at the very beginning. All settings that can be made through mysqlnd_ms_set_qos() can also be in the plugins configuration file. However, use of the function is by far the most common use case. Instead of setting session consistency and strong consistency service levels in the plugins configuration file it is recommended to define only masters and no slaves. Both service levels will force the use of masters only. Using an empty slave list shortens the configuration file, thus improving readability. The only service level for which there is a case of defining in the plugins configuration file is the combination of eventual consistency and maximum slave lag.Keyword Description Version eventual_consistencyRequest eventual consistency. Allows the use of all master and slave servers. Data returned may or may not be current.
Eventual consistency accepts an optional
ageparameter. Ifageis given the plugin considers only slaves for reading for which MySQL replication reports a slave lag less or equal toage. The replication lag is measure usingSHOW SLAVE STATUS. If the plugin fails to fetch the replication lag, the slave tested is skipped. Implementation details and tips are given in the quality of service concepts section.Please note, if a filter chain generates an empty slave list and the PHP configuration directive
mysqlnd_ms.multi_master=0is used, the plugin may emit a warning.Example #24 Global limit on slave lag
{ "myapp": { "master": { "master_0": { "host": "localhost" } }, "slave": { "slave_0": { "host": "192.168.2.27", "port": "3306" }, "slave_1": { "host": "192.168.78.136", "port": "3306" } }, "filters": { "quality_of_service": { "eventual_consistency": { "age":123 } } } } }Since 1.2.0. session_consistencyRequest session consistency (read your writes). Allows use of all masters and all slaves which are in sync with the master. If no further parameters are given slaves are filtered out as there is no reliable way to test if a slave has caught up to the master or is lagging behind. Please note, if a filter chain generates an empty slave list and the PHP configuration directive
mysqlnd_ms.multi_master=0is used, the plugin may emit a warning.Session consistency temporarily requested using mysqlnd_ms_set_qos() is a valuable alternative to using
master_on_write.master_on_writeis likely to send more statements to the master than needed. The application may be able to continue operation at a lower consistency level after it has done some critical reads.Since 1.1.0. strong_consistencyRequest strong consistency. Only masters will be used.
Since 1.2.0. -
failoverUp to and including 1.3.x: string. Since 1.4.0: object. -
Failover policy. Supported policies:
disabled(default),master,loop_before_master(Since 1.4.0).If no failover policy is set, the plugin will not do any automatic failover (
failover=disabled). Whenever the plugin fails to connect a server it will emit a warning and set the connections error code and message. Thereafter it is up to the application to handle the error and, for example, resent the last statement to trigger the selection of another server.Please note, the automatic failover logic is applied when opening connections only. Once a connection has been opened no automatic attempts are made to reopen it in case of an error. If, for example, the server a connection is connected to is shut down and the user attempts to run a statement on the connection, no automatic failover will be tried. Instead, an error will be reported.
If using
failover=masterthe plugin will implicitly failover to a master, if available. Please check the concepts documentation to learn about potential pitfalls and risks of usingfailover=master.Example #25 Optional master failover when failing to connect to slave (PECL/mysqlnd_ms < 1.4.0)
{ "myapp": { "master": { "master_0": { "host": "localhost" } }, "slave": { "slave_0": { "host": "192.168.78.136", "port": "3306" } }, "failover": "master" } }Since PECL/mysqlnd_ms 1.4.0 the failover configuration keyword refers to an object.
Example #26 New syntax since 1.4.0
{ "myapp": { "master": { "master_0": { "host": "localhost" } }, "slave": { "slave_0": { "host": "192.168.78.136", "port": "3306" } }, "failover": {"strategy": "master" } } }Keyword Description Version strategyFailover policy. Possible values:
disabled(default),master,loop_before_masterA value of
disableddisables automatic failover.Setting
masterinstructs the plugin to try to connect to a master in case of a slave connection error. If the master connection attempt fails, the plugin exists the failover loop and returns an error to the user.If using
loop_before_masterand a slave request is made, the plugin tries to connect to other slaves before failing over to a master. If multiple master are given and multi master is enabled, the plugin also loops over the list of masters and attempts to connect before returning an error to the user.Since 1.4.0. remember_failedRemember failures for the duration of a web request. Default:
false.If set to
truethe plugin will remember failed hosts and skip the hosts in all future load balancing made for the duration of the current web request.Since 1.4.0. The feature is only available together with the randomandroundrobinload balancing filter. Use of the setting is recommended.max_retriesMaximum number of connection attempts before skipping host. Default:
0(no limit).The setting is used to prevent hosts from being dropped of the host list upon the first failure. If set to
n > 0, the plugin will keep the node in the node list even after a failed connection attempt. The node will not be removed immediately from the slave respectively master lists after the first connection failure but instead be tried to connect to up tontimes in future load balancing rounds before being removed.Since 1.4.0. The feature is only available together with the randomandroundrobinload balancing filter.Setting
failoverto any other value butdisabled,masterorloop_before_masterwill not emit any warning or error. -
lazy_connectionsbool -
Controls the use of lazy connections. Lazy connections are connections which are not opened before the client sends the first connection. Lazy connections are a default.
It is strongly recommended to use lazy connections. Lazy connections help to keep the number of open connections low. If you disable lazy connections and, for example, configure one MySQL replication master server and two MySQL replication slaves, the plugin will open three connections upon the first call to a connect function although the application might use the master connection only.
Lazy connections bare a risk if you make heavy use of actions which change the state of a connection. The plugin does not dispatch all state changing actions to all connections from the connection pool. The few dispatched actions are applied to already opened connections only. Lazy connections opened in the future are not affected. Only some settings are "remembered" and applied when lazy connections are opened.
Example #27 Disabling lazy connection
{ "myapp": { "master": { "master_0": { "host": "localhost" } }, "slave": { "slave_0": { "host": "192.168.78.136", "port": "3306" } }, "lazy_connections": 0 } }Please, see also
server_charsetto overcome potential problems with string escaping and servers using different default charsets. -
server_charsetstring -
The setting has been introduced in 1.4.0. It is recommended to set it if using lazy connections.
The
server_charsetsetting serves two purposes. It acts as a fallback charset to be used for string escaping done before a connection has been established and it helps to avoid escaping pitfalls in heterogeneous environments which servers using different default charsets.String escaping takes a connections charset into account. String escaping is not possible before a connection has been opened and the connections charset is known. The use of lazy connections delays the actual opening of connections until a statement is send.
An application using lazy connections may attempt to escape a string before sending a statement. In fact, this should be a common case as the statement string may contain the string that is to be escaped. However, due to the lazy connection feature no connection has been opened yet and escaping fails. The plugin may report an error of the type
E_WARNINGand a message like(mysqlnd_ms) string escaping doesn't work without established connection. Possible solution is to add server_charset to your configurationto inform you of the pitfall.Setting
server_charsetmakes the plugin use the given charset for string escaping done on lazy connection handles before establishing a network connection to MySQL. Furthermore, the plugin will enforce the use of the charset when the connection is established.Enforcing the use of the configured charset used for escaping is done to prevent tapping into the pitfall of using a different charset for escaping than used later for the connection. This has the additional benefit of removing the need to align the charset configuration of all servers used. No matter what the default charset on any of the servers is, the plugin will set the configured one as a default.
The plugin does not stop the user from changing the charset at any time using the set_charset() call or corresponding SQL statements. Please, note that the use of SQL is not recommended as it cannot be monitored by the plugin. The user can, for example, change the charset on a lazy connection handle after escaping a string and before the actual connection is opened. The charset set by the user will be used for any subsequent escaping before the connection is established. The connection will be established using the configured charset, no matter what the server charset is or what the user has set before. Once a connection has been opened,
set_charsetis of no meaning anymore.Example #28 String escaping on a lazy connection handle
{ "myapp": { "master": { "master_0": { "host": "localhost" } }, "slave": { "slave_0": { "host": "192.168.78.136", "port": "3306" } }, "lazy_connections": 1, "server_charset" : "utf8" } }<?php
$mysqli = new mysqli("myapp", "username", "password", "database");
$mysqli->real_escape("this will be escaped using the server_charset setting - utf8");
$mysqli->set_charset("latin1");
$mysqli->real_escape("this will be escaped using latin1");
/* server_charset implicitly set - utf8 connection */
$mysqli->query("SELECT 'This connection will be set to server_charset upon establishing' AS _msg FROM DUAL");
/* latin1 used from now on */
$mysqli->set_charset("latin1");
?> -
master_on_writebool -
If set, the plugin will use the master server only after the first statement has been executed on the master. Applications can still send statements to the slaves using SQL hints to overrule the automatic decision.
The setting may help with replication lag. If an application runs an
INSERTthe plugin will, by default, use the master to execute all following statements, includingSELECTstatements. This helps to avoid problems with reads from slaves which have not replicated theINSERTyet.Example #29 Master on write for consistent reads
{ "myapp": { "master": { "master_0": { "host": "localhost" } }, "slave": { "slave_0": { "host": "192.168.78.136", "port": "3306" } }, "master_on_write": 1 } }Please, note the
quality_of_servicefilter introduced in version 1.2.0-alpha. It gives finer control, for example, for achieving read-your-writes and, it offers additional functionality introducing service levels.All transaction stickiness settings, including
trx_stickiness=on, are overruled bymaster_on_write=1. -
trx_stickinessstring -
Transaction stickiness policy. Supported policies:
disabled(default),master.The setting requires 5.4.0 or newer. If used with PHP older than 5.4.0, the plugin will emit a warning like
(mysqlnd_ms) trx_stickiness strategy is not supported before PHP 5.3.99.If no transaction stickiness policy is set or, if setting
trx_stickiness=disabled, the plugin is not transaction aware. Thus, the plugin may load balance connections and switch connections in the middle of a transaction. The plugin is not transaction safe. SQL hints must be used avoid connection switches during a transaction.As of PHP 5.4.0 the mysqlnd library allows the plugin to monitor the
autocommitmode set by calls to the librariesset_autocommit()function. If settingset_stickiness=masterandautocommitgets disabled by a PHP MySQL extension invoking themysqlndlibrary internal function callset_autocommit(), the plugin is made aware of the begin of a transaction. Then, the plugin stops load balancing and directs all statements to the master server untilautocommitis enabled. Thus, no SQL hints are required.An example of a PHP MySQL API function calling the
mysqlndlibrary internal function callset_autocommit()is mysqli_autocommit().Although setting
trx_stickiness=master, the plugin cannot be made aware ofautocommitmode changes caused by SQL statements such asSET AUTOCOMMIT=0orBEGIN.As of PHP 5.5.0, the mysqlnd library features additional C API calls to control transactions. The level of control matches the one offered by SQL statements. The
mysqliAPI has been modified to use these calls. Since version 1.5.0, PECL/mysqlnd_ms can monitor not only mysqli_autocommit(), but also mysqli_begin(), mysqli_commit() and mysqli_rollback() to detect transaction boundaries and stop load balancing for the duration of a transaction.Example #30 Using master to execute transactions
{ "myapp": { "master": { "master_0": { "host": "localhost" } }, "slave": { "slave_0": { "host": "192.168.78.136", "port": "3306" } }, "trx_stickiness": "master" } }Since version 1.5.0 automatic and silent failover is disabled for the duration of a transaction. If the boundaries of a transaction have been properly detected, transaction stickiness is enabled and a server fails, the plugin will not attempt to fail over to the next server, if any, regardless of the failover policy configured. The user must handle the error manually. Depending on the configuration, the plugin may emit an error of type
E_WARNINGreading like(mysqlnd_ms) Automatic failover is not permitted in the middle of a transaction. This error may then be overwritten by follow up errors such as(mysqlnd_ms) No connection selected by the last filter. Those errors will be generated by the failing query function.Example #31 No automatic failover, error handling pitfall
<?php
/* assumption: automatic failover configured */
$mysqli = new mysqli("myapp", "username", "password", "database");
/* sets plugin internal state in_trx = 1 */
$mysqli->autocommit(false);
/* assumption: server fails */
if (!($res = $mysqli->query("SELECT 'Assume this query fails' AS _msg FROM DUAL"))) {
/* handle failure of transaction, plugin internal state is still in_trx = 1 */
printf("[%d] %s", $mysqli->errno, $mysqli->error);
/*
If using autocommit() based transaction detection it is a
MUST to call autocommit(true). Otherwise the plugin assumes
the current transaction continues and connection
changes remain forbidden.
*/
$mysqli->autocommit(true);
/* Likewise, you'll want to start a new transaction */
$mysqli->autocommit(false);
}
/* latin1 used from now on */
$mysqli->set_charset("latin1");
?>If a server fails in the middle of a transaction the plugin continues to refuse to switch connections until the current transaction has been finished. Recall that the plugin monitors API calls to detect transaction boundaries. Thus, you have to, for example, enable auto commit mode to end the current transaction before the plugin continues load balancing and switches the server. Likewise, you will want to start a new transaction immediately thereafter and disable auto commit mode again.
Not handling failed queries and not ending a failed transaction using API calls may cause all following commands emit errors such as
Commands out of sync; you can't run this command now. Thus, it is important to handle all errors. -
transient_errorobject -
The setting has been introduced in 1.6.0.
A database cluster node may reply a transient error to a client. The client can then repeat the operation on the same node, fail over to a different node or abort the operation. Per definition is it safe for a client to retry the same operation on the same node before giving up.
PECL/mysqlnd_mscan perform the retry loop on behalf of the application. By configuringtransient_errorthe plugin can be instructed to repeat operations failing with a certain error code for a certain maximum number of times with a pause between the retries. If the transient error disappears during loop execution, it is hidden from the application. Otherwise, the error is forwarded to the application by the end of the loop.Example #32 Retry loop for transient errors
{ "myapp": { "master": { "master_0": { "host": "localhost" } }, "slave": { "slave_0": { "host": "192.168.78.136", "port": "3306" } }, "transient_error": { "mysql_error_codes": [ 1297 ], "max_retries": 2, "usleep_retry": 100 } } }Keyword Description Version mysql_error_codesList of transient error codes. You may add any MySQL error code to the list. It is possible to consider any error as transient not only
1297(HY000 (ER_GET_TEMPORARY_ERRMSG), Message: Got temporary error %d '%s' from %s). Before adding other codes but1297to the list, make sure your cluster supports a new attempt without impacting the state of your application.Since 1.6.0. max_retriesHow often to retry an operation which fails with a transient error before forwarding the failure to the user.
Default:
1Since 1.6.0. usleep_retryMilliseconds to sleep between transient error retries. The value is passed to the C function usleep(), hence the name.
Default:
100Since 1.6.0. -
xaobject -
The setting has been introduced in 1.6.0.
Note: Experimental
The feature is currently under development. There may be issues and/or feature limitations. Do not use in production environments.
- state_store
-
- record_participant_credentials
-
Whether to store the username and password of a global transaction participant in the participants table. If disabled, the garbage collection will use the default username and password when connecting to the participants. Unless you are using a different username and password for each of your MySQL servers, you can use the default and avoid storing the sensible information in state store.
Please note, username and password are stored in clear text when using the MySQL state store, which is the only one available. It is in your responsibility to protect this sensible information.
Default:
false - participant_localhost_ip
-
During XA garbage collection the plugin may find a participant server for which the host
localhosthas been recorded. If the garbage collection takes place on another host but the host that has written the participant record to the state store, the host namelocalhostnow resolves to a different host. Therefore, when recording a participant servers host name in the state store, a value oflocalhostmust be replaced with the actual IP address oflocalhost.Setting
participant_localhost_ipshould be considered only if usinglocalhostcannot be avoided. From a garbage collection point of view only, it is preferrable not to configure any socket connection but to provide an IP address and port for a node. - mysql
-
The MySQL state store is the only state store available.
- global_trx_table
-
Name of the MySQL table used to store the state of an ongoing or aborted global transaction. Use the below SQL statement to create the table. Make sure to edit the table name to match your configuration.
Default:
mysqlnd_ms_xa_trxExample #33 SQL definition for the MySQL state store transaction table
CREATE TABLE mysqlnd_ms_xa_trx ( store_trx_id int(11) NOT NULL AUTO_INCREMENT, gtrid int(11) NOT NULL, format_id int(10) unsigned NOT NULL DEFAULT '1', state enum('XA_NON_EXISTING','XA_ACTIVE','XA_IDLE','XA_PREPARED','XA_COMMIT','XA_ROLLBACK') NOT NULL DEFAULT 'XA_NON_EXISTING', intend enum('XA_NON_EXISTING','XA_ACTIVE','XA_IDLE','XA_PREPARED','XA_COMMIT','XA_ROLLBACK') DEFAULT 'XA_NON_EXISTING', finished enum('NO','SUCCESS','FAILURE') NOT NULL DEFAULT 'NO', modified timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, started datetime DEFAULT NULL, timeout datetime DEFAULT NULL, PRIMARY KEY (store_trx_id), KEY idx_xa_id (gtrid,format_id,finished), KEY idx_state (state) ) ENGINE=InnoDB - participant_table
-
Name of the MySQL table used to store participants of an ongoing or aborted global transaction. Use the below SQL statement to create the table. Make sure to edit the table name to match your configuration.
Storing credentials can be enabled and disabled using
record_participant_credentialsDefault:
mysqlnd_ms_xa_participantsExample #34 SQL definition for the MySQL state store transaction table
CREATE TABLE mysqlnd_ms_xa_participants ( fk_store_trx_id int(11) NOT NULL, bqual varbinary(64) NOT NULL DEFAULT '', participant_id int(10) unsigned NOT NULL AUTO_INCREMENT, server_uuid varchar(127) DEFAULT NULL, scheme varchar(1024) NOT NULL, host varchar(127) DEFAULT NULL, port smallint(5) unsigned DEFAULT NULL, socket varchar(127) DEFAULT NULL, user varchar(127) DEFAULT NULL, password varchar(127) DEFAULT NULL, state enum('XA_NON_EXISTING','XA_ACTIVE','XA_IDLE','XA_PREPARED','XA_COMMIT','XA_ROLLBACK') NOT NULL DEFAULT 'XA_NON_EXISTING', health enum('OK','GC_DONE','CLIENT ERROR','SERVER ERROR') NOT NULL DEFAULT 'OK', connection_id int(10) unsigned DEFAULT NULL, client_errno smallint(5) unsigned DEFAULT NULL, client_error varchar(1024) DEFAULT NULL, modified timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY (participant_id), KEY idx_xa_bqual (bqual), KEY idx_store_trx (fk_store_trx_id), CONSTRAINT mysqlnd_ms_xa_participants_ibfk_1 FOREIGN KEY (fk_store_trx_id) REFERENCES mysqlnd_ms_xa_trx (store_trx_id) ON DELETE CASCADE ON UPDATE CASCADE ) ENGINE=InnoDB - garbage_collection_table
-
Name of the MySQL table used to track and synchronize garbage collection runs. Use the below SQL statement to create the table. Make sure to edit the table name to match your configuration.
Default:
mysqlnd_ms_xa_gcExample #35 SQL definition for the MySQL state store garbage collection table
CREATE TABLE mysqlnd_ms_xa_gc ( gc_id int(10) unsigned NOT NULL AUTO_INCREMENT, gtrid int(11) NOT NULL, format_id int(10) unsigned NOT NULL DEFAULT '1', fk_store_trx_id int(11) DEFAULT NULL, modified timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, attempts smallint(5) unsigned NOT NULL DEFAULT '0', PRIMARY KEY (gc_id), KEY idx_store_trx (gtrid,format_id,fk_store_trx_id) ) ENGINE=InnoDB - host
-
Host name of the MySQL server.
- user
-
Name of the user used to connect to the MySQL server.
- password
-
Password for the MySQL server user.
- db
-
Database that holds the garbage collection tables. Please note, you have to create the garbage collection tables prior to using the plugin. The tables will not be created implicitly during runtime but garbage collection will fail if the tables to not exist.
- port
-
Port of the MySQL server.
- socket
-
Unix domain socket of the MySQL server. Please note, if you have multiple PHP servers each of them will try to carry out garbage collection and need to be able to connect to the state store. In this case, you may prefer configuring an IP address and a port for the MySQL state store server to ensure all PHP servers can reach it.
- rollback_on_close
-
Whether to automatically rollback an open global transaction when a connection is closed. If enabled, it mimics the default behaviour of local transactions. Should a client disconnect, the server rolls back any open and unfinished transactions.
Default:
true - garbage_collection
-
- max_retries
-
Maximum number of garbage collection runs before giving up. Allowed values are from
0to100. A setting of0means no limit, unless the state store enforces a limit. Should the state store enforce a limit, it can be supposed to be significantly higher than100. Available since 1.6.0.Please note, it is important to end failed XA transactions within reasonable time to make participating servers free resources bound to the transaction. The built-in garbage collection is not expected to fail for a long period as long as crashed servers become available again quickly. Still, a situation may arise where a human is required to act because the built-in garbage collection stopped or failed. In this case, you may first want to check if the transaction still cannot be fixed by forcing mysqlnd_ms_xa_gc() to ignore the setting, prior to handling it manually.
Default:
5 - probability
-
Garbage collection probability. Allowed values are from
0to1000. A setting of0disables automatic background garbage collection. Despite a setting of0it is still possible to trigger garbage collection by calling mysqlnd_ms_gc(). Available since 1.6.0.The automatic garbage collection of stalled XA transaction is only available if a state store have been configured. The state store is responsible to keep track of XA transactions. Based on its recordings it can find blocked XA transactions where the client has crashed, connect to the participants and rollback the unfinished transactions.
The garbage collection is triggered as part of PHP's request shutdown procedure at the end of a web request. That is after your PHP script has finished working. Do decide whether to run the garbage collection a random value between
0and1000is computed. If theprobabilityvalue is higher or equal to the random value, the state stores garbage collection routines are invoked.Default:
5 - max_transactions_per_run
-
Maximum number of unfinished XA transactions considered by the garbage collection during one run. Allowed values are from
1to32768. Available since 1.6.0.Cleaning up an unfinished XA transaction takes considerable amounts of time and resources. The garbage collection routine may have to connect to several participants of a failed global transaction to issue the SQL commands for rolling back the unfinished tranaction.
Default:
100
Plugin configuration file (<= 1.0.x)
Note:
The below description applies to PECL/mysqlnd_ms < 1.1.0-beta. It is not valid for later versions.
The plugin is using its own configuration file. The configuration file holds information on the MySQL replication master server, the MySQL replication slave servers, the server pick (load balancing) policy, the failover strategy and the use of lazy connections.
The PHP configuration directive
mysqlnd_ms.ini_file
is used to set the plugins configuration file.
The configuration file mimics standard the php.ini format.
It consists of one or more sections. Every section defines its own unit
of settings. There is no global section for setting defaults.
Applications reference sections by their name. Applications use section names as the host (server) parameter to the various connect methods of the mysqli, mysql and PDO_MYSQL extensions. Upon connect the mysqlnd plugin compares the hostname with all section names from the plugin configuration file. If hostname and section name match, the plugin will load the sections settings.
Example #36 Using section names example
[myapp] master[] = localhost slave[] = 192.168.2.27 slave[] = 192.168.2.28:3306 [localhost] master[] = localhost:/tmp/mysql/mysql.sock slave[] = 192.168.3.24:3305 slave[] = 192.168.3.65:3309
<?php
/* All of the following connections will be load balanced */
$mysqli = new mysqli("myapp", "username", "password", "database");
$pdo = new PDO('mysql:host=myapp;dbname=database', 'username', 'password');
$mysql = mysql_connect("myapp", "username", "password");
$mysqli = new mysqli("localhost", "username", "password", "database");
?>
Section names are strings. It is valid to use a section name such as
192.168.2.1, 127.0.0.1 or
localhost. If, for example, an application
connects to localhost and a plugin
configuration section [localhost] exists, the
semantics of the connect operation are changed. The application will
no longer only use the MySQL server running on the host
localhost but the plugin will start to load balance
MySQL queries following the rules from the [localhost]
configuration section. This way you can load balance queries from
an application without changing the applications source code.
The master[], slave[]
and pick[] configuration directives use a list-like syntax.
Configuration directives supporting list-like syntax may appear multiple
times in a configuration section. The plugin maintains the order in
which entries appear when interpreting them. For example,
the below example shows two slave[] configuration
directives in the configuration section [myapp].
If doing round-robin load balancing for read-only queries, the plugin
will send the first read-only query to the MySQL server
mysql_slave_1 because it is the first in the list.
The second read-only query will be send to the MySQL server
mysql_slave_2 because it is the second in the list.
Configuration directives supporting list-like syntax result are ordered
from top to bottom in accordance to their appearance within a configuration
section.
Example #37 List-like syntax
[myapp] master[] = mysql_master_server slave[] = mysql_slave_1 slave[] = mysql_slave_2
Here is a short explanation of the configuration directives that can be used.
-
master[]string -
URI of a MySQL replication master server. The URI follows the syntax
hostname[:port|unix_domain_socket].The plugin supports using only one master server.
Setting a master server is mandatory. The plugin will report a warning upon connect if the user has failed to provide a master server for a configuration section. The warning may read
(mysqlnd_ms) Cannot find master section in config. Furthermore the plugin may set an error code for the connection handle such asHY000/2000 (CR_UNKNOWN_ERROR). The corresponding error message depends on your language settings. -
slave[]string -
URI of one or more MySQL replication slave servers. The URI follows the syntax
hostname[:port|unix_domain_socket].The plugin supports using one or more slave servers.
Setting a slave server is mandatory. The plugin will report a warning upon connect if the user has failed to provide at least one slave server for a configuration section. The warning may read
(mysqlnd_ms) Cannot find slaves section in config. Furthermore the plugin may set an error code for the connection handle such asHY000/2000 (CR_UNKNOWN_ERROR). The corresponding error message depends on your language settings. -
pick[]string -
Load balancing (server picking) policy. Supported policies:
random,random_once(default),roundrobin,user.If no load balancing policy is set, the plugin will default to
random_once. Therandom_oncepolicy picks a random slave server when running the first read-only statement. The slave server will be used for all read-only statements until the PHP script execution ends.The
randompolicy will pick a random server whenever a read-only statement is to be executed.If using
roundrobinthe plugin iterates over the list of configured slave servers to pick a server for statement execution. If the plugin reaches the end of the list, it wraps around to the beginning of the list and picks the first configured slave server.Setting more than one load balancing policy for a configuration section makes only sense in conjunction with
userand mysqlnd_ms_set_user_pick_server(). If the user defined callback fails to pick a server, the plugin falls back to the second configured load balancing policy. -
failoverstring -
Failover policy. Supported policies:
disabled(default),master.If no failover policy is set, the plugin will not do any automatic failover (
failover=disabled). Whenever the plugin fails to connect a server it will emit a warning and set the connections error code and message. Thereafter it is up to the application to handle the error and, for example, resent the last statement to trigger the selection of another server.If using
failover=masterthe plugin will implicitly failover to a slave, if available. Please check the concepts documentation to learn about potential pitfalls and risks of usingfailover=master. -
lazy_connectionsbool -
Controls the use of lazy connections. Lazy connections are connections which are not opened before the client sends the first connection.
It is strongly recommended to use lazy connections. Lazy connections help to keep the number of open connections low. If you disable lazy connections and, for example, configure one MySQL replication master server and two MySQL replication slaves, the plugin will open three connections upon the first call to a connect function although the application might use the master connection only.
Lazy connections bare a risk if you make heavy use of actions which change the state of a connection. The plugin does not dispatch all state changing actions to all connections from the connection pool. The few dispatched actions are applied to already opened connections only. Lazy connections opened in the future are not affected. If, for example, the connection character set is changed using a PHP MySQL API call, the plugin will change the character set of all currently opened connection. It will not remember the character set change to apply it on lazy connections opened in the future. As a result the internal connection pool would hold connections using different character sets. This is not desired. Remember that character sets are taken into account for escaping.
-
master_on_writebool -
If set, the plugin will use the master server only after the first statement has been executed on the master. Applications can still send statements to the slaves using SQL hints to overrule the automatic decision.
The setting may help with replication lag. If an application runs an
INSERTthe plugin will, by default, use the master to execute all following statements, includingSELECTstatements. This helps to avoid problems with reads from slaves which have not replicated theINSERTyet. -
trx_stickinessstring -
Transaction stickiness policy. Supported policies:
disabled(default),master.Experimental feature.
The setting requires 5.4.0 or newer. If used with PHP older than 5.4.0, the plugin will emit a warning like
(mysqlnd_ms) trx_stickiness strategy is not supported before PHP 5.3.99.If no transaction stickiness policy is set or, if setting
trx_stickiness=disabled, the plugin is not transaction aware. Thus, the plugin may load balance connections and switch connections in the middle of a transaction. The plugin is not transaction safe. SQL hints must be used avoid connection switches during a transaction.As of PHP 5.4.0 the mysqlnd library allows the plugin to monitor the
autocommitmode set by calls to the librariestrx_autocommit()function. If settingtrx_stickiness=masterandautocommitgets disabled by a PHP MySQL extension invoking themysqlndlibrary internal function calltrx_autocommit(), the plugin is made aware of the begin of a transaction. Then, the plugin stops load balancing and directs all statements to the master server untilautocommitis enabled. Thus, no SQL hints are required.An example of a PHP MySQL API function calling the
mysqlndlibrary internal function calltrx_autocommit()is mysqli_autocommit().Although setting
trx_stickiness=master, the plugin cannot be made aware ofautocommitmode changes caused by SQL statements such asSET AUTOCOMMIT=0.
Testing
Note:
The section applies to mysqlnd_ms 1.1.0 or newer, not the 1.0 series.
The PECL/mysqlnd_ms test suite is in the tests/ directory of the source distribution. The test suite consists of standard phpt tests, which are described on the PHP Quality Assurance Teams website.
Running the tests requires setting up one to four MySQL servers. Some tests don't connect to MySQL at all. Others require one server for testing. Some require two distinct servers. In some cases two servers are used to emulate a replication setup. In other cases a master and a slave of an existing MySQL replication setup are required for testing. The tests will try to detect how many servers and what kind of servers are given. If the required servers are not found, the test will be skipped automatically.
Before running the tests, edit tests/config.inc to configure the MySQL servers to be used for testing.
The most basic configuration is as follows.
putenv("MYSQL_TEST_HOST=localhost");
putenv("MYSQL_TEST_PORT=3306");
putenv("MYSQL_TEST_USER=root");
putenv("MYSQL_TEST_PASSWD=");
putenv("MYSQL_TEST_DB=test");
putenv("MYSQL_TEST_ENGINE=MyISAM");
putenv("MYSQL_TEST_SOCKET=");
putenv("MYSQL_TEST_SKIP_CONNECT_FAILURE=1");
putenv("MYSQL_TEST_CONNECT_FLAGS=0");
putenv("MYSQL_TEST_EXPERIMENTAL=0");
/* replication cluster emulation */
putenv("MYSQL_TEST_EMULATED_MASTER_HOST=". getenv("MYSQL_TEST_HOST"));
putenv("MYSQL_TEST_EMULATED_SLAVE_HOST=". getenv("MYSQL_TEST_HOST"));
/* real replication cluster */
putenv("MYSQL_TEST_MASTER_HOST=". getenv("MYSQL_TEST_EMULATED_MASTER_HOST"));
putenv("MYSQL_TEST_SLAVE_HOST=". getenv("MYSQL_TEST_EMULATED_SLAVE_HOST"));
MYSQL_TEST_HOST, MYSQL_TEST_PORT and
MYSQL_TEST_SOCKET define the hostname,
TCP/IP port and Unix domain socket of the default database server.
MYSQL_TEST_USER and MYSQL_TEST_PASSWD
contain the user and password needed to connect to the database/schema
configured with MYSQL_TEST_DB. All configured
servers must have the same database user configured to give access to
the test database.
Using host, host:port or host:/path/to/socket
syntax one can set an alternate host, host and port or host and socket for any
of the servers.
putenv("MYSQL_TEST_SLAVE_HOST=192.168.78.136:3307"));
putenv("MYSQL_TEST_MASTER_HOST=myserver_hostname:/path/to/socket"));
Debugging and Tracing
The mysqlnd debug log can be used to debug and trace the actitivities of
PECL/mysqlnd_ms. As a mysqlnd PECL/mysqlnd_ms adds trace information to the
mysqlnd library debug file. Please, see the
mysqlnd.debug
PHP configuration directive documentation for a detailed description
on how to configure the debug log.
Configuration setting example to activate the debug log:
mysqlnd.debug=d:t:x:O,/tmp/mysqlnd.trace
Note:
This feature is only available with a debug build of PHP. Works on Microsoft Windows if using a debug build of PHP and PHP was built using Microsoft Visual C version 9 and above.
The debug log shows mysqlnd library and PECL/mysqlnd_ms plugin function calls,
similar to a trace log. Mysqlnd library calls are usually prefixed with
mysqlnd_. PECL/mysqlnd internal calls begin with
mysqlnd_ms.
Example excerpt from the debug log (connect):
[...] >mysqlnd_connect | info : host=myapp user=root db=test port=3306 flags=131072 | >mysqlnd_ms::connect | | >mysqlnd_ms_config_json_section_exists | | | info : section=[myapp] len=[5] | | | >mysqlnd_ms_config_json_sub_section_exists | | | | info : section=[myapp] len=[5] | | | | info : ret=1 | | | <mysqlnd_ms_config_json_sub_section_exists | | | info : ret=1 | | <mysqlnd_ms_config_json_section_exists [...]
The debug log is not only useful for plugin developers but also to find the cause of user errors. For example, if your application does not do proper error handling and fails to record error messages, checking the debug and trace log may help finding the cause. Use of the debug log to debug application issues should be considered only if no other option is available. Writing the debug log to disk is a slow operation and may have negative impact on the application performance.
Example excerpt from the debug log (connection failure):
[...] | | | | | | | info : adding error [Access denied for user 'root'@'localhost' (using password: YES)] to the list | | | | | | | info : PACKET_FREE(0) | | | | | | | info : PACKET_FREE(0x7f3ef6323f50) | | | | | | | info : PACKET_FREE(0x7f3ef6324080) | | | | | | <mysqlnd_auth_handshake | | | | | | info : switch_to_auth_protocol=n/a | | | | | | info : conn->error_info.error_no = 1045 | | | | | <mysqlnd_connect_run_authentication | | | | | info : PACKET_FREE(0x7f3ef63236d8) | | | | | >mysqlnd_conn::free_contents | | | | | | >mysqlnd_net::free_contents | | | | | | <mysqlnd_net::free_contents | | | | | | info : Freeing memory of members | | | | | | info : scheme=unix:///tmp/mysql.sock | | | | | | >mysqlnd_error_list_pdtor | | | | | | <mysqlnd_error_list_pdtor | | | | | <mysqlnd_conn::free_contents | | | | <mysqlnd_conn::connect [...]
The trace log can also be used to verify correct behaviour of PECL/mysqlnd_ms itself, for example, to check which server has been selected for query execution and why.
Example excerpt from the debug log (plugin decision):
[...] >mysqlnd_ms::query | info : query=DROP TABLE IF EXISTS test | >_mysqlnd_plugin_get_plugin_connection_data | | info : plugin_id=5 | <_mysqlnd_plugin_get_plugin_connection_data | >mysqlnd_ms_pick_server_ex | | info : conn_data=0x7fb6a7d3e5a0 *conn_data=0x7fb6a7d410d0 | | >mysqlnd_ms_select_servers_all | | <mysqlnd_ms_select_servers_all | | >mysqlnd_ms_choose_connection_rr | | | >mysqlnd_ms_query_is_select [...] | | | <mysqlnd_ms_query_is_select [...] | | | info : Init the master context | | | info : list(0x7fb6a7d3f598) has 1 | | | info : Using master connection | | | >mysqlnd_ms_advanced_connect | | | | >mysqlnd_conn::connect | | | | | info : host=localhost user=root db=test port=3306 flags=131072 persistent=0 state=0
In this case the statement DROP TABLE IF EXISTS test has been
executed. Note that the statement string is shown in the log file. You may want
to take measures to restrict access to the log for security considerations.
The statement has been load balanced using round robin policy,
as you can easily guess from the functions name >mysqlnd_ms_choose_connection_rr.
It has been sent to a master server running on
host=localhost user=root db=test port=3306 flags=131072 persistent=0 state=0.
Monitoring
Plugin activity can be monitored using the mysqlnd trace log, mysqlnd statistics, mysqlnd_ms plugin statistics and external PHP debugging tools. Use of the trace log should be limited to debugging. It is recommended to use the plugins statistics for monitoring.
Writing a trace log is a slow operation. If using an external PHP debugging tool, please refer to the vendors manual about its performance impact and the type of information collected. In many cases, external debugging tools will provide call stacks. Often, a call stack or a trace log is more difficult to interpret than the statistics provided by the plugin.
Plugin statistics tell how often which kind of cluster node has been used (slave or master), why the node was used, if lazy connections have been used and if global transaction ID injection has been performed. The monitoring information provided enables user to verify plugin decisions and to plan their cluster resources based on usage pattern. The function mysqlnd_ms_get_stats() is used to access the statistics. Please, see the functions description for a list of available statistics.
Statistics are collected on a per PHP process basis. Their scope is a PHP process. Depending on the PHP deployment model a process may serve one or multiple web requests. If using CGI model, a PHP process serves one web request. If using FastCGI or pre-fork web server models, a PHP process usually serves multiple web requests. The same is the case with a threaded web server. Please, note that threads running in parallel can update the statistics in parallel. Thus, if using a threaded PHP deployment model, statistics can be changed by more than one script at a time. A script cannot rely on the fact that it sees only its own changes to statistics.
Example #38 Verify plugin activity in a non-threaded deployment model
mysqlnd_ms.enable=1 mysqlnd_ms.collect_statistics=1
<?php
/* Load balanced following "myapp" section rules from the plugins config file (not shown) */
$mysqli = new mysqli("myapp", "username", "password", "database");
if (mysqli_connect_errno())
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
$stats_before = mysqlnd_ms_get_stats();
if ($res = $mysqli->query("SELECT 'Read request' FROM DUAL")) {
var_dump($res->fetch_all());
}
$stats_after = mysqlnd_ms_get_stats();
if ($stats_after['use_slave'] <= $stats_before['use_slave']) {
echo "According to the statistics the read request has not been run on a slave!";
}
?>
Statistics are aggregated for all plugin activities and all connections handled by the plugin. It is not possible to tell how much a certain connection handle has contributed to the overall statistics.
Utilizing PHPs register_shutdown_function() function or the
auto_append_file PHP configuration directive it is
easily possible to dump statistics into, for example, a log file when a script
finishes. Instead of using a log file it is also possible to send the statistics
to an external monitoring tool for recording and display.
Example #39 Recording statistics during shutdown
mysqlnd_ms.enable=1 mysqlnd_ms.collect_statistics=1 error_log=/tmp/php_errors.log
<?php
function check_stats() {
$msg = str_repeat("-", 80) . "\n";
$msg .= var_export(mysqlnd_ms_get_stats(), true) . "\n";
$msg .= str_repeat("-", 80) . "\n";
error_log($msg);
}
register_shutdown_function("check_stats");
?>
Predefined Constants
The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
SQL hint related
Example #1 Example demonstrating the usage of mysqlnd_ms constants
The mysqlnd replication and load balancing plugin (mysqlnd_ms)
performs read/write splitting. This directs write queries to a MySQL
master server, and read-only queries to the MySQL slave servers.
The plugin has a built-in read/write split logic.
All queries which start with SELECT are considered read-only
queries, which are then sent to a MySQL slave server that is listed in
the plugin configuration file. All other queries are directed to the
MySQL master server that is also specified in the plugin configuration file.
User supplied SQL hints can be used to overrule automatic read/write splitting, to gain full control on the process. SQL hints are standards compliant SQL comments. The plugin will scan the beginning of a query string for an SQL comment for certain commands, which then control query redirection. Other systems involved in the query processing are unaffected by the SQL hints because other systems will ignore the SQL comments.
The plugin supports three SQL hints to direct queries to either the MySQL slave servers, the MySQL master server, or the last used MySQL server. SQL hints must be placed at the beginning of a query to be recognized by the plugin.
For better portability, it is recommended to use the string constants
MYSQLND_MS_MASTER_SWITCH,
MYSQLND_MS_SLAVE_SWITCH and
MYSQLND_MS_LAST_USED_SWITCH instead of their literal
values.
<?php
/* Use constants for maximum portability */
$master_query = "/*" . MYSQLND_MS_MASTER_SWITCH . "*/SELECT id FROM test";
/* Valid but less portable: using literal instead of constant */
$slave_query = "/*ms=slave*/SHOW TABLES";
printf("master_query = '%s'\n", $master_query);
printf("slave_query = '%s'\n", $slave_query);
?>
The above examples will output:
master_query = /*ms=master*/SELECT id FROM test slave_query = /*ms=slave*/SHOW TABLES
-
MYSQLND_MS_MASTER_SWITCH(string) - SQL hint used to send a query to the MySQL replication master server.
-
MYSQLND_MS_SLAVE_SWITCH(string) - SQL hint used to send a query to one of the MySQL replication slave servers.
-
MYSQLND_MS_LAST_USED_SWITCH(string) - SQL hint used to send a query to the last used MySQL server. The last used MySQL server can either be a master or a slave server in a MySQL replication setup.
mysqlnd_ms_query_is_select() related
-
MYSQLND_MS_QUERY_USE_MASTER(integer) -
If mysqlnd_ms_is_select() returns
MYSQLND_MS_QUERY_USE_MASTERfor a given query, the built-in read/write split mechanism recommends sending the query to a MySQL replication master server. -
MYSQLND_MS_QUERY_USE_SLAVE(integer) -
If mysqlnd_ms_is_select() returns
MYSQLND_MS_QUERY_USE_SLAVEfor a given query, the built-in read/write split mechanism recommends sending the query to a MySQL replication slave server. -
MYSQLND_MS_QUERY_USE_LAST_USED(integer) -
If mysqlnd_ms_is_select() returns
MYSQLND_MS_QUERY_USE_LAST_USEDfor a given query, the built-in read/write split mechanism recommends sending the query to the last used server.
mysqlnd_ms_set_qos(), quality of service filter and service level related
-
MYSQLND_MS_QOS_CONSISTENCY_EVENTUAL(integer) - Use to request the service level eventual consistency from the mysqlnd_ms_set_qos(). Eventual consistency is the default quality of service when reading from an asynchronous MySQL replication slave. Data returned in this service level may or may not be stale, depending on whether the selected slaves happen to have replicated the latest changes from the MySQL replication master or not.
-
MYSQLND_MS_QOS_CONSISTENCY_SESSION(integer) - Use to request the service level session consistency from the mysqlnd_ms_set_qos(). Session consistency is defined as read your writes. The client is guaranteed to see his latest changes.
-
MYSQLND_MS_QOS_CONSISTENCY_STRONG(integer) - Use to request the service level strong consistency from the mysqlnd_ms_set_qos(). Strong consistency is used to ensure all clients see each others changes.
-
MYSQLND_MS_QOS_OPTION_GTID(integer) - Used as a service level option with mysqlnd_ms_set_qos() to parameterize session consistency.
-
MYSQLND_MS_QOS_OPTION_AGE(integer) - Used as a service level option with mysqlnd_ms_set_qos() to parameterize eventual consistency.
Other
The plugins version number can be obtained using
MYSQLND_MS_VERSION or
MYSQLND_MS_VERSION_ID.
MYSQLND_MS_VERSION
is the string representation of the numerical version number
MYSQLND_MS_VERSION_ID, which is an integer such as 10000.
Developers can calculate the version number as follows.
| Version (part) | Example |
|---|---|
| Major*10000 | 1*10000 = 10000 |
| Minor*100 | 0*100 = 0 |
| Patch | 0 = 0 |
| MYSQLND_MS_VERSION_ID | 10000 |
Mysqlnd_ms Functions
mysqlnd_ms_dump_servers
(No version information available, might only be in Git)
mysqlnd_ms_dump_servers — Returns a list of currently configured servers
Description
Returns a list of currently configured servers.
Parameters
Return Values
FALSE on error. Otherwise, returns an array with two entries
masters and slaves each of which contains
an array listing all corresponding servers.
The function can be used to check and debug the list of servers currently used by the plugin. It is mostly useful when the list of servers changes at runtime, for example, when using MySQL Fabric.
masters and slaves server entries
| Key | Description | Version |
|---|---|---|
name_from_config
|
Server entry name from config, if appliciable. NULL if no configuration name is available. |
Since 1.6.0. |
hostname
|
Host name of the server. |
Since 1.6.0. |
user
|
Database user used to authenticate against the server. |
Since 1.6.0. |
port
|
TCP/IP port of the server. |
Since 1.6.0. |
socket
|
Unix domain socket of the server. |
Since 1.6.0. |
Notes
Note:
mysqlnd_ms_dump_servers() requires PECL mysqlnd_ms >> 1.6.0.
Examples
Example #1 mysqlnd_ms_dump_servers() example
{
"myapp": {
"master": {
"master1": {
"host":"master1_host",
"port":"master1_port",
"socket":"master1_socket",
"db":"master1_db",
"user":"master1_user",
"password":"master1_pw"
}
},
"slave": {
"slave_0": {
"host":"slave0_host",
"port":"slave0_port",
"socket":"slave0_socket",
"db":"slave0_db",
"user":"slave0_user",
"password":"slave0_pw"
},
"slave_1": {
"host":"slave1_host"
}
}
}
}
<?php
$link = mysqli_connect("myapp", "global_user", "global_pass", "global_db", 1234, "global_socket");
var_dump(mysqlnd_ms_dump_servers($link);
?>
The above example will output:
array(2) {
["masters"]=>
array(1) {
[0]=>
array(5) {
["name_from_config"]=>
string(7) "master1"
["hostname"]=>
string(12) "master1_host"
["user"]=>
string(12) "master1_user"
["port"]=>
int(3306)
["socket"]=>
string(14) "master1_socket"
}
}
["slaves"]=>
array(2) {
[0]=>
array(5) {
["name_from_config"]=>
string(7) "slave_0"
["hostname"]=>
string(11) "slave0_host"
["user"]=>
string(11) "slave0_user"
["port"]=>
int(3306)
["socket"]=>
string(13) "slave0_socket"
}
[1]=>
array(5) {
["name_from_config"]=>
string(7) "slave_1"
["hostname"]=>
string(11) "slave1_host"
["user"]=>
string(12) "gloabal_user"
["port"]=>
int(1234)
["socket"]=>
string(13) "global_socket"
}
}
}
mysqlnd_ms_fabric_select_global
(No version information available, might only be in Git)
mysqlnd_ms_fabric_select_global — Switch to global sharding server for a given table
Description
This function is currently not documented; only its argument list is available.
MySQL Fabric related.
Switch the connection to the nodes handling global sharding queries for the given table name.
Parameters
Return Values
FALSE on error. Otherwise, TRUE
Notes
Note:
mysqlnd_ms_fabric_select_global() requires PECL mysqlnd_ms >> 1.6.0.
mysqlnd_ms_fabric_select_shard
(No version information available, might only be in Git)
mysqlnd_ms_fabric_select_shard — Switch to shard
Description
This function is currently not documented; only its argument list is available.
MySQL Fabric related.
Switch the connection to the shards responsible for the given table name and shard key.
Parameters
Return Values
FALSE on error. Otherwise, TRUE
Notes
Note:
mysqlnd_ms_fabric_select_shard() requires PECL mysqlnd_ms >> 1.6.0.
mysqlnd_ms_get_last_gtid
(PECL mysqlnd_ms >= 1.2.0)
mysqlnd_ms_get_last_gtid — Returns the latest global transaction ID
Description
Returns a global transaction identifier which belongs to a write operation no older than the last write performed by the client. It is not guaranteed that the global transaction identifier is identical to that one created for the last write transaction performed by the client.
Parameters
Return Values
Returns a global transaction ID (GTID) on success.
Otherwise, returns FALSE.
The function mysqlnd_ms_get_last_gtid() returns the
GTID obtained when executing the SQL statement from
the fetch_last_gtid entry of the
global_transaction_id_injection section from
the plugins configuration file.
The function may be called after the GTID has been incremented.
Notes
Note:
mysqlnd_ms_get_last_gtid() requires PHP >= 5.4.0 and PECL mysqlnd_ms >= 1.2.0. Internally, it is using a
mysqlndlibrary C functionality not available with PHP 5.3.Please note, all MySQL 5.6 production versions do not provide clients with enough information to use GTIDs for enforcing session consistency. In the worst case, the plugin will choose the master only.
Examples
Example #1 mysqlnd_ms_get_last_gtid() example
<?php
/* Open mysqlnd_ms connection using mysqli, PDO_MySQL or mysql extension */
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli)
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
/* auto commit mode, transaction on master, GTID must be incremented */
if (!$mysqli->query("DROP TABLE IF EXISTS test"))
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
printf("GTID after transaction %s\n", mysqlnd_ms_get_last_gtid($mysqli));
/* auto commit mode, transaction on master, GTID must be incremented */
if (!$mysqli->query("CREATE TABLE test(id INT)"))
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
printf("GTID after transaction %s\n", mysqlnd_ms_get_last_gtid($mysqli));
?>
mysqlnd_ms_get_last_used_connection
(PECL mysqlnd_ms >= 1.1.0)
mysqlnd_ms_get_last_used_connection — Returns an array which describes the last used connection
Description
Returns an array which describes the last used connection from the plugins connection pool currently pointed to by the user connection handle. If using the plugin, a user connection handle represents a pool of database connections. It is not possible to tell from the user connection handles properties to which database server from the pool the user connection handle points.
The function can be used to debug or monitor PECL mysqlnd_ms.
Parameters
Return Values
FALSE on error. Otherwise, an
array which describes the connection used to
execute the last statement on.
Array which describes the connection.
| Property | Description | Version |
|---|---|---|
scheme
|
Connection scheme. Either tcp://host:port
or unix://host:socket. If you want to
distinguish connections from each other use a combination
of scheme and thread_id as a unique
key. Neither scheme nor thread_id
alone are sufficient to distinguish two connections from each other.
Two servers may assign the same thread_id to two
different connections. Thus, connections in the pool may have the same
thread_id. Also, do not rely on uniqueness of
scheme in a pool. Your QA engineers may use the
same MySQL server instance for two distinct logical roles and add it
multiple times to the pool. This hack is used, for example,
in the test suite.
|
Since 1.1.0. |
host
|
Database server host used with the connection. The host is only set with TCP/IP connections. It is empty with Unix domain or Windows named pipe connections, | Since 1.1.0. |
host_info
|
A character string representing the server hostname and the connection type. | Since 1.1.2. |
port
|
Database server port used with the connection. | Since 1.1.0. |
socket_or_pipe
|
Unix domain socket or Windows named pipe used with the connection. The value is empty for TCP/IP connections. | Since 1.1.2. |
thread_id
|
Connection thread id. | Since 1.1.0. |
last_message
|
Info message obtained from the MySQL C API function mysql_info(). Please, see mysqli_info() for a description. | Since 1.1.0. |
errno
|
Error code. | Since 1.1.0. |
error
|
Error message. | Since 1.1.0. |
sqlstate
|
Error SQLstate code. | Since 1.1.0. |
Notes
Note:
mysqlnd_ms_get_last_used_connection() requires PHP >= 5.4.0 and PECL mysqlnd_ms >> 1.1.0. Internally, it is using a
mysqlndlibrary C call not available with PHP 5.3.
Examples
The example assumes that myapp refers to a
plugin configuration file section and represents a connection pool.
Example #1 mysqlnd_ms_get_last_used_connection() example
<?php
$link = new mysqli("myapp", "user", "password", "database");
$res = $link->query("SELECT 1 FROM DUAL");
var_dump(mysqlnd_ms_get_last_used_connection($link));
?>
The above example will output:
array(10) {
["scheme"]=>
string(22) "unix:///tmp/mysql.sock"
["host_info"]=>
string(25) "Localhost via UNIX socket"
["host"]=>
string(0) ""
["port"]=>
int(3306)
["socket_or_pipe"]=>
string(15) "/tmp/mysql.sock"
["thread_id"]=>
int(46253)
["last_message"]=>
string(0) ""
["errno"]=>
int(0)
["error"]=>
string(0) ""
["sqlstate"]=>
string(5) "00000"
}
mysqlnd_ms_get_stats
(PECL mysqlnd_ms >= 1.0.0)
mysqlnd_ms_get_stats — Returns query distribution and connection statistics
Description
Returns an array of statistics collected by the replication and load balancing plugin.
The PHP configuration setting
mysqlnd_ms.collect_statistics
controls the collection of statistics. The collection of statistics
is disabled by default for performance reasons.
The scope of the statistics is the
PHP process.
Depending on your deployment model a
PHP process may handle one or multiple requests.
Statistics are aggregated for all connections and all storage handler. It is not possible
to tell how much queries originating from
mysqli,
PDO_MySQL or
mysql API calls have
contributed to the aggregated data values.
Parameters
This function has no parameters.
Return Values
Returns NULL if
the PHP configuration directive
mysqlnd_ms.enable
has disabled the plugin. Otherwise, returns array of statistics.
Array of statistics
| Statistic | Description | Version |
|---|---|---|
use_slave
|
The semantics of this statistic has changed between 1.0.1 - 1.1.0.
The meaning for version 1.0.1 is as follows.
Number of statements considered as read-only by the built-in query analyzer.
Neither statements which begin with a SQL hint to force
use of slave nor statements directed to a slave by an user-defined
callback are included. The total number of statements sent to the slaves is
PECL/mysqlnd_ms 1.1.0 introduces a new concept of chained filters. The
statistics is now set by the internal load balancing filter. With
version 1.1.0 the load balancing filter is always the last in the
filter chain, if used. In future versions a load balancing filter may be
followed by other filters causing another change in the meaning of
the statistic. If, in the future, a load balancing filter is followed
by another filter it is no longer guaranteed that the statement, which
increments
The meaning for version 1.1.0 is as follows. Number of statements
sent to the slaves. Statements directed to a slave by the user filter
(an user-defined callback) are not included. The latter are counted by
|
Since 1.0.0. |
use_master
|
The semantics of this statistic has changed between 1.0.1 - 1.1.0.
The meaning for version 1.0.1 is as follows.
Number of statements not considered as read-only by the built-in query analyzer.
Neither statements which begin with a SQL hint to force
use of master nor statements directed to a master by an user-defined
callback are included. The total number of statements sent to the master is
PECL/mysqlnd_ms 1.1.0 introduces a new concept of chained filters. The
statictics is now set by the internal load balancing filter. With
version 1.1.0 the load balancing filter is always the last in the
filter chain, if used. In future versions a load balancing filter may be
followed by other filters causing another change in the meaning of
the statistic. If, in the future, a load balancing filter is followed
by another filter it is no longer guaranteed that the statement, which
increments
The meaning for version 1.1.0 is as follows. Number of statements
sent to the masters. Statements directed to a master by the user filter
(an user-defined callback) are not included. The latter are counted by
|
Since 1.0.0. |
use_slave_guess
|
Number of statements the built-in query analyzer recommends sending to
a slave because they contain no SQL hint to force use of a
certain server. The recommendation may be overruled in the following.
It is not guaranteed whether the statement will be executed on a slave
or not. This is how often the internal is_select
function has guessed that a slave shall be used. Please, see also the
user space function mysqlnd_ms_query_is_select().
|
Since 1.1.0. |
use_master_guess
|
Number of statements the built-in query analyzer recommends sending to
a master because they contain no SQL hint to force use of a
certain server. The recommendation may be overruled in the following.
It is not guaranteed whether the statement will be executed on a slave
or not. This is how often the internal is_select
function has guessed that a master shall be used. Please, see also the
user space function mysqlnd_ms_query_is_select().
|
Since 1.1.0. |
use_slave_sql_hint
|
Number of statements sent to a slave because statement begins with the SQL hint to force use of slave. | Since 1.0.0. |
use_master_sql_hint
|
Number of statements sent to a master because statement begins with the SQL hint to force use of master. | Since 1.0.0. |
use_last_used_sql_hint
|
Number of statements sent to server which has run the previous statement, because statement begins with the SQL hint to force use of previously used server. | Since 1.0.0. |
use_slave_callback
|
Number of statements sent to a slave because an user-defined callback has chosen a slave server for statement execution. | Since 1.0.0. |
use_master_callback
|
Number of statements sent to a master because an user-defined callback has chosen a master server for statement execution. | Since 1.0.0. |
non_lazy_connections_slave_success
|
Number of successfully opened slave connections from
configurations not using
lazy connections.
The total number of successfully opened slave connections
is non_lazy_connections_slave_success +
lazy_connections_slave_success
|
Since 1.0.0. |
non_lazy_connections_slave_failure
|
Number of failed slave connection attempts from
configurations not using
lazy connections.
The total number of failed slave connection attempts
is non_lazy_connections_slave_failure +
lazy_connections_slave_failure
|
Since 1.0.0. |
non_lazy_connections_master_success
|
Number of successfully opened master connections from
configurations not using
lazy connections.
The total number of successfully opened master connections
is non_lazy_connections_master_success +
lazy_connections_master_success
|
Since 1.0.0. |
non_lazy_connections_master_failure
|
Number of failed master connection attempts from
configurations not using
lazy connections.
The total number of failed master connection attempts
is non_lazy_connections_master_failure +
lazy_connections_master_failure
|
Since 1.0.0. |
lazy_connections_slave_success
|
Number of successfully opened slave connections from
configurations using
lazy connections.
|
Since 1.0.0. |
lazy_connections_slave_failure
|
Number of failed slave connection attempts from
configurations using
lazy connections.
|
Since 1.0.0. |
lazy_connections_master_success
|
Number of successfully opened master connections from
configurations using
lazy connections.
|
Since 1.0.0. |
lazy_connections_master_failure
|
Number of failed master connection attempts from
configurations using
lazy connections.
|
Since 1.0.0. |
trx_autocommit_on
|
Number of autocommit mode activations via API calls.
This figure may be used to monitor activity related to the plugin configuration
setting
trx_stickiness.
If, for example, you want to know if a certain API call invokes the
mysqlnd library function trx_autocommit(),
which is a requirement for
trx_stickiness,
you may call the user API function in question and check if the
statistic has changed. The statistic is modified only by the
plugins internal subclassed trx_autocommit()
method.
|
Since 1.0.0. |
trx_autocommit_off
|
Number of autocommit mode deactivations via API calls.
|
Since 1.0.0. |
trx_master_forced
|
Number of statements redirected to the master while
trx_stickiness=master
and autocommit mode is disabled.
|
Since 1.0.0. |
gtid_autocommit_injections_success
|
Number of successful SQL injections in autocommit mode as part of the plugins client-side global transaction id emulation. | Since 1.2.0. |
gtid_autocommit_injections_failure
|
Number of failed SQL injections in autocommit mode as part of the plugins client-side global transaction id emulation. | Since 1.2.0. |
gtid_commit_injections_success
|
Number of successful SQL injections in commit mode as part of the plugins client-side global transaction id emulation. | Since 1.2.0. |
gtid_commit_injections_failure
|
Number of failed SQL injections in commit mode as part of the plugins client-side global transaction id emulation. | Since 1.2.0. |
gtid_implicit_commit_injections_success
|
Number of successful SQL injections when implicit commit is detected as part
of the plugins client-side
global transaction id emulation.
Implicit commit happens, for example, when autocommit has been turned
off, a query is executed and autocommit is enabled again. In that case,
the statement will be committed by the server and SQL to maintain is
injected before the autocommit is re-enabled. Another sequence
causing an implicit commit is begin(),
query(), begin(). The second call
to begin() will implicitly commit the transaction
started by the first call to begin().
begin() refers to internal library calls not actual
PHP user API calls.
|
Since 1.2.0. |
gtid_implicit_commit_injections_failure
|
Number of failed SQL injections when implicit commit is detected as part of the plugins client-side global transaction id emulation. Implicit commit happens, for example, when autocommit has been turned off, a query is executed and autocommit is enabled again. In that case, the statement will be committed by the server and SQL to maintain is injected before the autocommit is re-enabled. | Since 1.2.0. |
transient_error_retries
|
How often an operation has been retried when a transient error was
detected. See also,
transient_error
plugin configuration file setting.
|
Since 1.6.0. |
fabric_sharding_lookup_servers_success
|
Number of successful sharding.lookup_servers
remote procedure calls to MySQL Fabric.
A call is considered successful if the plugin could reach MySQL
Fabric and got any reply. The reply itself may or may not be
understood by the plugin. Success refers to the network transport
only. If the reply was not understood or indicates a valid error condition,
fabric_sharding_lookup_servers_xml_failure
gets incremented.
|
Since 1.6.0. |
fabric_sharding_lookup_servers_failure
|
Number of failed sharding.lookup_servers
remote procedure calls to MySQL Fabric.
A remote procedure call is considered failed if there was a
network error in connecting to, writing to or reading from
MySQL Fabric.
|
Since 1.6.0. |
fabric_sharding_lookup_servers_time_total
|
Time spent connecting to,writing to and reading from MySQL
Fabrich during the sharding.lookup_servers
remote procedure call. The value is aggregated for all calls. Time is
measured in microseconds.
|
Since 1.6.0. |
fabric_sharding_lookup_servers_bytes_total
|
Total number of bytes received from MySQL Fabric in reply to
sharding.lookup_servers calls.
|
Since 1.6.0. |
fabric_sharding_lookup_servers_xml_failure
|
How often a reply from MySQL Fabric to
sharding.lookup_servers calls was not understood.
Please note, the current experimental implementation does not
distinguish between valid errors returned and malformed replies.
|
Since 1.6.0. |
xa_begin
|
How many XA/distributed transactions have been started using mysqlnd_ms_xa_begin(). | Since 1.6.0. |
xa_commit_success
|
How many XA/distributed transactions have been successfully committed using mysqlnd_ms_xa_commit(). | Since 1.6.0. |
xa_commit_failure
|
How many XA/distributed transactions failed to commit during mysqlnd_ms_xa_commit(). | Since 1.6.0. |
xa_rollback_success
|
How many XA/distributed transactions have been successfully rolled back using mysqlnd_ms_xa_rollback(). The figure does not include implict rollbacks performed as a result of mysqlnd_ms_xa_commit() failure. | Since 1.6.0. |
xa_rollback_failure
|
How many XA/distributed transactions could not be rolled back.
This includes failures of mysqlnd_ms_xa_rollback()
but also failured during rollback when closing a connection, if
rollback_on_close is set. Please, see also
xa_rollback_on_close below.
|
Since 1.6.0. |
xa_participants
|
Total number of participants in any XA transaction started with mysqlnd_ms_xa_begin(). | Since 1.6.0. |
xa_rollback_on_close
|
How many XA transactions have been rolled back implicitly when
a connection was close and rollback_on_close is set.
Depending on your coding policies, this may hint a flaw in your code as
you may prefer to explicitly clean up resources.
|
Since 1.6.0. |
pool_masters_total
|
Number of master servers (connections) in the internal connection pool. | Since 1.6.0. |
pool_slaves_total
|
Number of slave servers (connections) in the internal connection pool. | Since 1.6.0. |
pool_masters_active
|
Number of master servers (connections) from the internal connection pool which are currently used for picking a connection. | Since 1.6.0. |
pool_slaves_active
|
Number of slave servers (connections) from the internal connection pool which are currently used for picking a connection. | Since 1.6.0. |
pool_updates
|
How often the active connection list has been replaced and a new set of master and slave servers had been installed. | Since 1.6.0. |
pool_master_reactivated
|
How often a master connection has been reused after being flushed from the active list. | Since 1.6.0. |
pool_slave_reactivated
|
How often a slave connection has been reused after being flushed from the active list. | Since 1.6.0. |
Examples
Example #1 mysqlnd_ms_get_stats() example
<?php
printf("mysqlnd_ms.enable = %d\n", ini_get("mysqlnd_ms.enable"));
printf("mysqlnd_ms.collect_statistics = %d\n", ini_get("mysqlnd_ms.collect_statistics"));
var_dump(mysqlnd_ms_get_stats());
?>
The above example will output:
mysqlnd_ms.enable = 1
mysqlnd_ms.collect_statistics = 1
array(26) {
["use_slave"]=>
string(1) "0"
["use_master"]=>
string(1) "0"
["use_slave_guess"]=>
string(1) "0"
["use_master_guess"]=>
string(1) "0"
["use_slave_sql_hint"]=>
string(1) "0"
["use_master_sql_hint"]=>
string(1) "0"
["use_last_used_sql_hint"]=>
string(1) "0"
["use_slave_callback"]=>
string(1) "0"
["use_master_callback"]=>
string(1) "0"
["non_lazy_connections_slave_success"]=>
string(1) "0"
["non_lazy_connections_slave_failure"]=>
string(1) "0"
["non_lazy_connections_master_success"]=>
string(1) "0"
["non_lazy_connections_master_failure"]=>
string(1) "0"
["lazy_connections_slave_success"]=>
string(1) "0"
["lazy_connections_slave_failure"]=>
string(1) "0"
["lazy_connections_master_success"]=>
string(1) "0"
["lazy_connections_master_failure"]=>
string(1) "0"
["trx_autocommit_on"]=>
string(1) "0"
["trx_autocommit_off"]=>
string(1) "0"
["trx_master_forced"]=>
string(1) "0"
["gtid_autocommit_injections_success"]=>
string(1) "0"
["gtid_autocommit_injections_failure"]=>
string(1) "0"
["gtid_commit_injections_success"]=>
string(1) "0"
["gtid_commit_injections_failure"]=>
string(1) "0"
["gtid_implicit_commit_injections_success"]=>
string(1) "0"
["gtid_implicit_commit_injections_failure"]=>
string(1) "0"
["transient_error_retries"]=>
string(1) "0"
}
mysqlnd_ms_match_wild
(PECL mysqlnd_ms >= 1.1.0)
mysqlnd_ms_match_wild — Finds whether a table name matches a wildcard pattern or not
Description
$table_name
, string $wildcard
) : boolFinds whether a table name matches a wildcard pattern or not.
This function is not of much practical relevance with PECL mysqlnd_ms 1.1.0 because the plugin does not support MySQL replication table filtering yet.
Parameters
-
table_name -
The table name to check if it is matched by the wildcard.
-
wildcard -
The wildcard pattern to check against the table name. The wildcard pattern supports the same placeholders as MySQL replication filters do.
MySQL replication filters can be configured by using the MySQL Server configuration options
--replicate-wild-do-tableand--replicate-wild-do-db. Please, consult the MySQL Reference Manual to learn more about this MySQL Server feature.The supported placeholders are:
-
%- zero or more literals -
_- one literal
Placeholders can be escaped using
\. -
Return Values
Returns TRUE table_name is
matched by wildcard.
Otherwise, returns FALSE
Examples
Example #1 mysqlnd_ms_match_wild() example
<?php
var_dump(mysqlnd_ms_match_wild("schema_name.table_name", "schema%"));
var_dump(mysqlnd_ms_match_wild("abc", "_"));
var_dump(mysqlnd_ms_match_wild("table1", "table_"));
var_dump(mysqlnd_ms_match_wild("asia_customers", "%customers"));
var_dump(mysqlnd_ms_match_wild("funny%table","funny\%table"));
var_dump(mysqlnd_ms_match_wild("funnytable", "funny%table"));
?>
The above example will output:
bool(true) bool(false) bool(true) bool(true) bool(true) bool(true)
mysqlnd_ms_query_is_select
(PECL mysqlnd_ms >= 1.0.0)
mysqlnd_ms_query_is_select — Find whether to send the query to the master, the slave or the last used MySQL server
Description
$query
) : intFinds whether to send the query to the master, the slave or the last used MySQL server.
The plugins built-in read/write split mechanism
will be used to analyze the query string to make a recommendation where
to send the query. The built-in read/write split mechanism is very
basic and simple. The plugin will recommend sending all queries to the
MySQL replication master server but those which begin with
SELECT, or begin with a SQL hint which
enforces sending the query to a slave server. Due to the basic
but fast algorithm the plugin may propose to run some read-only
statements such as SHOW TABLES on the replication master.
Parameters
-
query -
Query string to test.
Return Values
A return value of MYSQLND_MS_QUERY_USE_MASTER
indicates that the query should be send to the MySQL replication
master server. The function returns a value of
MYSQLND_MS_QUERY_USE_SLAVE if the query can be run
on a slave because it is considered read-only. A value of
MYSQLND_MS_QUERY_USE_LAST_USED is returned to recommend
running the query on the last used server. This can either be a MySQL
replication master server or a MySQL replication slave server.
If read write splitting has been disabled by setting
mysqlnd_ms.disable_rw_split, the function will
always return MYSQLND_MS_QUERY_USE_MASTER or
MYSQLND_MS_QUERY_USE_LAST_USED.
Examples
Example #1 mysqlnd_ms_query_is_select() example
<?php
function is_select($query)
{
switch (mysqlnd_ms_query_is_select($query))
{
case MYSQLND_MS_QUERY_USE_MASTER:
printf("'%s' should be run on the master.\n", $query);
break;
case MYSQLND_MS_QUERY_USE_SLAVE:
printf("'%s' should be run on a slave.\n", $query);
break;
case MYSQLND_MS_QUERY_USE_LAST_USED:
printf("'%s' should be run on the server that has run the previous query\n", $query);
break;
default:
printf("No suggestion where to run the '%s', fallback to master recommended\n", $query);
break;
}
}
is_select("INSERT INTO test(id) VALUES (1)");
is_select("SELECT 1 FROM DUAL");
is_select("/*" . MYSQLND_MS_LAST_USED_SWITCH . "*/SELECT 2 FROM DUAL");
?>
The above example will output:
INSERT INTO test(id) VALUES (1) should be run on the master. SELECT 1 FROM DUAL should be run on a slave. /*ms=last_used*/SELECT 2 FROM DUAL should be run on the server that has run the previous query
mysqlnd_ms_set_qos
(PECL mysqlnd_ms < 1.2.0)
mysqlnd_ms_set_qos — Sets the quality of service needed from the cluster
Description
$connection
, int $service_level
[, int $service_level_option
[, mixed $option_value
]] ) : boolSets the quality of service needed from the cluster. A database cluster delivers a certain quality of service to the user depending on its architecture. A major aspect of the quality of service is the consistency level the cluster can offer. An asynchronous MySQL replication cluster defaults to eventual consistency for slave reads: a slave may serve stale data, current data, or it may have not the requested data at all, because it is not synchronous to the master. In a MySQL replication cluster, only master accesses can give strong consistency, which promises that all clients see each others changes.
PECL/mysqlnd_ms hides the complexity of choosing appropriate nodes to achieve a certain level of service from the cluster. The "Quality of Service" filter implements the necessary logic. The filter can either be configured in the plugins configuration file, or at runtime using mysqlnd_ms_set_qos().
Similar results can be achieved with PECL mysqlnd_ms < 1.2.0, if using
SQL hints to force the use of a certain type of node or using the
master_on_write plugin configuration option. The first
requires more code and causes more work on the application side.
The latter is less refined than using the quality of service filter.
Settings made through the function call can be reversed, as shown in the example
below. The example temporarily switches to a higher service level
(session consistency, read your writes) and returns
back to the clusters default after it has performed all operations that require the
better service. This way, read load on the master can be minimized compared to
using master_on_write, which would continue using the master
after the first write.
Since 1.5.0 calls will fail when done in the middle of a transaction if transaction stickiness is enabled and transaction boundaries have been detected. properly.
Parameters
-
connection -
A PECL/mysqlnd_ms connection handle to a MySQL server of the type PDO_MYSQL, mysqli or ext/mysql for which a service level is to be set. The connection handle is obtained when opening a connection with a host name that matches a mysqlnd_ms configuration file entry using any of the above three MySQL driver extensions.
-
service_level -
The requested service level:
MYSQLND_MS_QOS_CONSISTENCY_EVENTUAL,MYSQLND_MS_QOS_CONSISTENCY_SESSIONorMYSQLND_MS_QOS_CONSISTENCY_STRONG. -
service_level_option -
An option to parameterize the requested service level. The option can either be
MYSQLND_MS_QOS_OPTION_GTIDorMYSQLND_MS_QOS_OPTION_AGE.The option
MYSQLND_MS_QOS_OPTION_GTIDcan be used to refine the service levelMYSQLND_MS_QOS_CONSISTENCY_SESSION. It must be combined with a fourth function parameter, theoption_value. Theoption_valueshall be a global transaction ID obtained from mysqlnd_ms_get_last_gtid(). If set, the plugin considers both master servers and asynchronous slaves for session consistency (read your writes). Otherwise, only masters are used to achieve session consistency. A slave is considered up-to-date and checked if it has already replicated the global transaction ID fromoption_value. Please note, searching appropriate slaves is an expensive and slow operation. Use the feature sparsely, if the master cannot handle the read load alone.The
MYSQLND_MS_QOS_OPTION_AGEoption can be combined with theMYSQLND_MS_QOS_CONSISTENCY_EVENTUALservice level, to filter out asynchronous slaves that lag more seconds behind the master thanoption_value. If set, the plugin will only consider slaves for reading ifSHOW SLAVE STATUSreportsSlave_IO_Running=Yes,Slave_SQL_Running=YesandSeconds_Behind_Master <= option_value. Please note, searching appropriate slaves is an expensive and slow operation. Use the feature sparsely in version 1.2.0. Future versions may improve the algorithm used to identify candidates. Please, see the MySQL reference manual about the precision, accuracy and limitations of the MySQL administrative commandSHOW SLAVE STATUS. -
option_value -
Parameter value for the service level option. See also the
service_level_optionparameter.
Return Values
Returns TRUE if the connections service level
has been switched to the requested. Otherwise, returns FALSE
Notes
Note:
mysqlnd_ms_set_qos() requires PHP >= 5.4.0 and PECL mysqlnd_ms >= 1.2.0. Internally, it is using a
mysqlndlibrary C functionality not available with PHP 5.3.Please note, all MySQL 5.6 production versions do not provide clients with enough information to use GTIDs for enforcing session consistency. In the worst case, the plugin will choose the master only.
Examples
Example #1 mysqlnd_ms_set_qos() example
<?php
/* Open mysqlnd_ms connection using mysqli, PDO_MySQL or mysql extension */
$mysqli = new mysqli("myapp", "username", "password", "database");
if (!$mysqli)
/* Of course, your error handling is nicer... */
die(sprintf("[%d] %s\n", mysqli_connect_errno(), mysqli_connect_error()));
/* Session consistency: read your writes */
$ret = mysqlnd_ms_set_qos($mysqli, MYSQLND_MS_QOS_CONSISTENCY_SESSION);
if (!$ret)
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
/* Will use master and return fresh data, client can see his last write */
if (!$res = $mysqli->query("SELECT item, price FROM orders WHERE order_id = 1"))
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
/* Back to default: use of all slaves and masters permitted, stale data can happen */
if (!mysqlnd_ms_set_qos($mysqli, MYSQLND_MS_QOS_CONSISTENCY_EVENTUAL))
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
?>
See Also
- mysqlnd_ms_get_last_gtid() - Returns the latest global transaction ID
- Service level and consistency concept
- Filter concept
mysqlnd_ms_set_user_pick_server
(PECL mysqlnd_ms < 1.1.0)
mysqlnd_ms_set_user_pick_server — Sets a callback for user-defined read/write splitting
Description
$function
) : bool
Sets a callback for user-defined read/write splitting. The plugin will
call the callback only if pick[]=user is the default
rule for server picking in the relevant section of the plugins configuration
file.
The plugins built-in read/write query split mechanism decisions can be
overwritten in two ways. The easiest way is to prepend the query string
with the SQL hints MYSQLND_MS_MASTER_SWITCH,
MYSQLND_MS_SLAVE_SWITCH or
MYSQLND_MS_LAST_USED_SWITCH. Using SQL hints one can
control, for example, whether a query shall be send to the MySQL replication
master server or one of the slave servers. By help of SQL hints it is
not possible to pick a certain slave server for query execution.
Full control on server selection can be gained using a callback function. Use of a callback is recommended to expert users only because the callback has to cover all cases otherwise handled by the plugin.
The plugin will invoke the callback function for selecting a server from the lists of configured master and slave servers. The callback function inspects the query to run and picks a server for query execution by returning the hosts URI, as found in the master and slave list.
If the lazy connections are enabled and the callback chooses a slave server for which no connection has been established so far and establishing the connection to the slave fails, the plugin will return an error upon the next action on the failed connection, for example, when running a query. It is the responsibility of the application developer to handle the error. For example, the application can re-run the query to trigger a new server selection and callback invocation. If so, the callback must make sure to select a different slave, or check slave availability, before returning to the plugin to prevent an endless loop.
Parameters
-
function -
The function to be called. Class methods may also be invoked statically using this function by passing
array($classname, $methodname)to this parameter. Additionally class methods of an object instance may be called by passingarray($objectinstance, $methodname)to this parameter.
Return Values
Host to run the query on. The host URI is to be taken from the
master and slave connection lists passed to the callback function.
If callback returns a value neither found in the master nor in the slave
connection lists the plugin will fallback to the second pick method configured
via the pick[] setting in the plugin configuration file.
If not second pick method is given, the plugin falls back to the build-in
default pick method for server selection.
Notes
Note:
mysqlnd_ms_set_user_pick_server() is available with PECL mysqlnd_ms < 1.1.0. It has been replaced by the
userfilter. Please, check the Change History for upgrade notes.
Examples
Example #1 mysqlnd_ms_set_user_pick_server() example
[myapp] master[] = localhost slave[] = 192.168.2.27:3306 slave[] = 192.168.78.136:3306 pick[] = user
<?php
function pick_server($connected, $query, $master, $slaves, $last_used)
{
static $slave_idx = 0;
static $num_slaves = NULL;
if (is_null($num_slaves))
$num_slaves = count($slaves);
/* default: fallback to the plugins build-in logic */
$ret = NULL;
printf("User has connected to '%s'...\n", $connected);
printf("... deciding where to run '%s'\n", $query);
$where = mysqlnd_ms_query_is_select($query);
switch ($where)
{
case MYSQLND_MS_QUERY_USE_MASTER:
printf("... using master\n");
$ret = $master[0];
break;
case MYSQLND_MS_QUERY_USE_SLAVE:
/* SELECT or SQL hint for using slave */
if (stristr($query, "FROM table_on_slave_a_only"))
{
/* a table which is only on the first configured slave */
printf("... access to table available only on slave A detected\n");
$ret = $slaves[0];
}
else
{
/* round robin */
printf("... some read-only query for a slave\n");
$ret = $slaves[$slave_idx++ % $num_slaves];
}
break;
case MYSQLND_MS_QUERY_LAST_USED:
printf("... using last used server\n");
$ret = $last_used;
break;
}
printf("... ret = '%s'\n", $ret);
return $ret;
}
mysqlnd_ms_set_user_pick_server("pick_server");
$mysqli = new mysqli("myapp", "root", "root", "test");
if (!($res = $mysqli->query("SELECT 1 FROM DUAL")))
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
else
$res->close();
if (!($res = $mysqli->query("SELECT 2 FROM DUAL")))
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
else
$res->close();
if (!($res = $mysqli->query("SELECT * FROM table_on_slave_a_only")))
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
else
$res->close();
$mysqli->close();
?>
The above example will output:
User has connected to 'myapp'... ... deciding where to run 'SELECT 1 FROM DUAL' ... some read-only query for a slave ... ret = 'tcp://192.168.2.27:3306' User has connected to 'myapp'... ... deciding where to run 'SELECT 2 FROM DUAL' ... some read-only query for a slave ... ret = 'tcp://192.168.78.136:3306' User has connected to 'myapp'... ... deciding where to run 'SELECT * FROM table_on_slave_a_only' ... access to table available only on slave A detected ... ret = 'tcp://192.168.2.27:3306'
See Also
- mysqlnd_ms_query_is_select() - Find whether to send the query to the master, the slave or the last used MySQL server
- Filter concept
-
userfilter
mysqlnd_ms_xa_begin
(PECL mysqlnd_ms < 1.6.0)
mysqlnd_ms_xa_begin — Starts a distributed/XA transaction among MySQL servers
Description
Starts a XA transaction among MySQL servers. PECL/mysqlnd_ms acts as a transaction coordinator the distributed transaction.
Once a global transaction has been started, the plugin injects appropriate
XA BEGIN SQL statements on all MySQL servers used in the following.
The global transaction is either ended by calling mysqlnd_ms_xa_commit(),
mysqlnd_ms_xa_rollback() or by an implicit rollback in case
of an error.
During a global transaction, the plugin tracks all server switches,
for example, when switching from one MySQL shard to another MySQL shard.
Immediately before a query is run on a server that has not been participating
in the global transaction yet, XA BEGIN is executed on
the server. From a users perspective the injection happens during a call to a
query execution function such as mysqli_query(). Should
the injection fail an error is reported to the caller of the query execution
function. The failing server does not become a participant in the global
transaction. The user may retry executing a query on the server and hereby retry
injecting XA BEGIN, abort the global transaction because
not all required servers can participate, or ignore and continue the global without
the failed server.
Reasons to fail executing XA BEGIN include but are not limited to
a server being unreachable or the server having an open, concurrent
XA transaction using the same xid.
Please note, global and local transactions
are mutually exclusive. You cannot start a XA transaction when you have a local
transaction open. The local transaction must be ended first. The plugin tries
to detect this conflict as early as possible. It monitors API calls for controlling
local transactions to learn about the current state. However, if using
SQL statements for local transactions such as BEGIN, the
plugin may not know the current state and the conflict is not detected
before XA BEGIN is injected and executed.
The use of other XA resources but MySQL servers is not supported by the function. To carry out a global transaction among, for example, a MySQL server and another vendors database system, you should issue the systems SQL commands yourself.
Note: Experimental
The feature is currently under development. There may be issues and/or feature limitations. Do not use in production environments.
Parameters
-
connection -
A MySQL connection handle obtained from any of the connect functions of the mysqli, mysql or PDO_MYSQL extensions.
-
gtrid -
Global transaction identifier (gtrid). The gtrid is a binary string up to 64 bytes long. Please note, depending on your character set settings, 64 characters may require more than 64 bytes to store.
In accordance with the MySQL SQL syntax, XA transactions use identifiers made of three parts. An xid consists of a global transaction identifier (gtrid), a branch qualifier (bqual) and a format identifier (formatID). Only the global transaction identifier can and needs to be set.
The branch qualifier and format identifier are set automatically. The details should be considered implementation dependent, which may change without prior notice. In version 1.6 the branch qualifier is consecutive number which is incremented whenever a participant joins the global transaction.
-
timeout -
Timeout in seconds. The default value is 60 seconds.
The timeout is a hint to the garbage collection. If a transaction is recorded to take longer than expected, the garbage collection begins checking the transactions status.
Setting a low value may make the garbage collection check the progress too often. Please note, checking the status of a global transaction may involve connecting to all recorded participants and possibly issuing queries on the servers.
Return Values
Returns TRUE if there is no open local or global transaction and a new global
transaction can be started. Otherwise, returns FALSE
See Also
- Quickstart XA/Distributed transactions
- Runtime configuration
- mysqlnd_ms_get_stats() - Returns query distribution and connection statistics
mysqlnd_ms_xa_commit
(PECL mysqlnd_ms < 1.6.0)
mysqlnd_ms_xa_commit — Commits a distributed/XA transaction among MySQL servers
Description
Commits a global transaction among MySQL servers started by mysqlnd_ms_xa_begin().
If any of the global transaction participants fails to commit an implicit rollback is performed. It may happen that not all cases can be handled during the rollback. For example, no attempts will be made to reconnect to a participant after the connection to the participant has been lost. Solving cases that cannot easily be rolled back is left to the garbage collection.
Note: Experimental
The feature is currently under development. There may be issues and/or feature limitations. Do not use in production environments.
Parameters
Return Values
Returns TRUE if the global transaction has been committed. Otherwise, returns FALSE
See Also
- Quickstart XA/Distributed transactions
- Runtime configuration
- mysqlnd_ms_get_stats() - Returns query distribution and connection statistics
mysqlnd_ms_xa_gc
(PECL mysqlnd_ms < 1.6.0)
mysqlnd_ms_xa_gc — Garbage collects unfinished XA transactions after severe errors
Description
Garbage collects unfinished XA transactions.
The XA protocol is a blocking protocol. There exist cases when servers participating in a global transaction cannot make progress when the transaction coordinator crashes or disconnects. In such a case, the MySQL servers keep waiting for instructions to finish the XA transaction in question. Because transactions occupy resources, transactions should always be terminated properly.
Garbage collection requires configuring a state store to track global transactions. Should a PHP client crash in the middle of a transaction and a new PHP client be started, then the built-in garbage collection can learn about the aborted global transaction and terminate it. If you do not configure a state store, the garbage collection cannot perform any cleanup tasks.
The state store should be crash-safe and be highly available to survive its own crash. Currently, only MySQL is supported as a state store.
Garbage collection can also be performed automatically in the background.
See the plugin configuration directive garbage_collection
for details.
Note: Experimental
The feature is currently under development. There may be issues and/or feature limitations. Do not use in production environments.
Parameters
-
connection -
A MySQL connection handle obtained from any of the connect functions of the mysqli, mysql or PDO_MYSQL extensions.
-
gtrid -
Global transaction identifier (gtrid). If given, the garbage collection considers the transaction only. Otherwise, the state store is scanned for any unfinished transaction.
-
ignore_max_retries -
Whether to ignore the plugin configuration
max_retriessetting. If garbage collection continuously fails and themax_retrieslimit is reached prior to finishing the failed global transaction, you can attempt further runs prior to investigating the cause and solving the issue manually by issuing appropriate SQL statements on the participants. Setting the parameter has the same effect as temporarily settingmax_retries = 0.
Return Values
Returns TRUE if garbage collection was successful. Otherwise, returns FALSE
See Also
- Quickstart XA/Distributed transactions
- Runtime configuration
- State store configuration
- mysqlnd_ms_get_stats() - Returns query distribution and connection statistics
mysqlnd_ms_xa_rollback
(PECL mysqlnd_ms < 1.6.0)
mysqlnd_ms_xa_rollback — Rolls back a distributed/XA transaction among MySQL servers
Description
Rolls back a global transaction among MySQL servers started by mysqlnd_ms_xa_begin().
If any of the global transaction participants fails to rollback the situation is left to be solved by the garbage collection.
Note: Experimental
The feature is currently under development. There may be issues and/or feature limitations. Do not use in production environments.
Parameters
Return Values
Returns TRUE if the global transaction has been rolled back. Otherwise, returns FALSE
See Also
- Quickstart XA/Distributed transactions
- Runtime configuration
- mysqlnd_ms_get_stats() - Returns query distribution and connection statistics
Table of Contents
- mysqlnd_ms_dump_servers — Returns a list of currently configured servers
- mysqlnd_ms_fabric_select_global — Switch to global sharding server for a given table
- mysqlnd_ms_fabric_select_shard — Switch to shard
- mysqlnd_ms_get_last_gtid — Returns the latest global transaction ID
- mysqlnd_ms_get_last_used_connection — Returns an array which describes the last used connection
- mysqlnd_ms_get_stats — Returns query distribution and connection statistics
- mysqlnd_ms_match_wild — Finds whether a table name matches a wildcard pattern or not
- mysqlnd_ms_query_is_select — Find whether to send the query to the master, the slave or the last used MySQL server
- mysqlnd_ms_set_qos — Sets the quality of service needed from the cluster
- mysqlnd_ms_set_user_pick_server — Sets a callback for user-defined read/write splitting
- mysqlnd_ms_xa_begin — Starts a distributed/XA transaction among MySQL servers
- mysqlnd_ms_xa_commit — Commits a distributed/XA transaction among MySQL servers
- mysqlnd_ms_xa_gc — Garbage collects unfinished XA transactions after severe errors
- mysqlnd_ms_xa_rollback — Rolls back a distributed/XA transaction among MySQL servers
Change History
Table of Contents
- PECL/mysqlnd_ms 1.6 series
- PECL/mysqlnd_ms 1.5 series
- PECL/mysqlnd_ms 1.4 series
- PECL/mysqlnd_ms 1.3 series
- PECL/mysqlnd_ms 1.2 series
- PECL/mysqlnd_ms 1.1 series
- PECL/mysqlnd_ms 1.0 series
This change history is a high level summary of selected changes that may impact applications and/or break backwards compatibility.
See also the CHANGES file in the source distribution for a complete list of changes.
PECL/mysqlnd_ms 1.6 series
1.6.0-alpha
- Release date: TBD
- Motto/theme: Maintenance and initial MySQL Fabric support
Note:
This is the current development series. All features are at an early stage. Changes may happen at any time without prior notice. Please, do not use this version in production environments.
The documentation may not reflect all changes yet.
Bug fixes
-
Won't fix: #66616 R/W split fails: QOS with mysqlnd_get_last_gtid with built-in MySQL GTID
This is not a bug in the plugins implementation but a server side feature limitation not considered and documented before. MySQL 5.6 built-in GTIDs cannot be used to ensure session consistency when reading from slaves in all cases. In the worst case the plugin will not consider using the slaves and fallback to using the master. There will be no wrong results but no benefit from doing GTID checks either.
-
Fixed #66064 - Random once load balancer ignoring weights
Due to a config parsing bug random load balancing has ignored node weights if, and only if, the sticky flag was set (random once).
-
Fixed #65496 - Wrong check for slave delay
The quality of service filter has erroneously ignored slaves that lag for zero (0) seconds if a any maximum lag had been set. Although a slave was not lagging behind, it was excluded from the load balancing list if a maximum age was set by the QoS filter. This was due to using the wrong comparison operator in the source of the filter.
-
Fixed #65408 - Compile failure with -Werror=format-security
Feature changes
-
Introduced an internal connection pool. When using Fabric and switching from shard group A to shard group B, we are replacing the entire list of masters and slaves. This troubles the connections state alignment logic and some filters. Some filters cache information on the master and slave lists. The new internal connection pool abstraction allows us to inform the filters of changes, hence they can update their caches.
Later on, the pool can also be used to reduce connection overhead. Assume you are switching from a shard group to another and back again. Whenever the switch is done, the pool's active server (and connection) lists are replaced. However, no longer used connections are not necessarily closed immediately but can be kept in the pool for later reuse.
Please note, the connection pool is internalat this point. There are some new statistics to monitor it. However, you cannot yet configure pool size of behaviour.
-
Added a basic distributed transaction abstraction. XA transactions can are supported ever since using standard SQL calls. This is inconvenient as XA participants must be managed manually. PECL/mysqlnd_ms introduces API calls to control XA transaction among MySQL servers. When using the new functions, PECL/mysqlnd_ms acts as a transaction coordinator. After starting a distributed transaction, the plugin tracks all servers involved until the transaction is ended and issues appropriate SQL statements on the XA participants.
This is useful, for example, when using Fabric and sharding. When using Fabric the actual shard servers involved in a business transaction may not be known in advance. Thus, manually controlling a transaction that spawns multiple shards becomes difficult. Please, be warned about current limitations.
-
Introduced automatic retry loop for transient errors and corresponding statistic to count the number of implicit retries. Some distributed database clusters use transient errors to hint a client to retry its operation in a bit. Most often, the client is then supposed to halt execution (sleep) for a short moment before retrying the desired operation. Immediately failing over to another node is not necessary in response to the error. Instead, a retry loop can be performed. Common situation when using MySQL Cluster.
-
Introduced automatic retry loop for transient errors and corresponding statistic to count the number of implicit retries. Some distributed database clusters use transient errors to hint a client to retry its operation in a bit. Most often, the client is then supposed to halt execution (sleep) for a short moment before retrying the desired operation. Immediately failing over to another node is not necessary in response to the error. Instead, a retry loop can be performed. Common situation when using MySQL Cluster.
-
Introduced most basic support for the MySQL Fabric High Availability and sharding framework.
Please, consider this pre-alpha quality. Both the server side framework and the client side code is supposed to work flawless considering the MySQL Fabric quickstart examples only. However, testing has not been performed to the level of prior plugin alpha releases. Either sides are moving targets, API changes may happen at any time without prior warning.
As this is work in progress, the manual may not yet reflect allow feature limitations and known bugs.
-
New statistics to monitor the Fabric XML RPC call
sharding.lookup_servers:fabric_sharding_lookup_servers_success,fabric_sharding_lookup_servers_failure,fabric_sharding_lookup_servers_time_total,fabric_sharding_lookup_servers_bytes_total,fabric_sharding_lookup_servers_xml_failure. -
New functions related to MySQL Fabric: mysqlnd_ms_fabric_select_shard(), mysqlnd_ms_fabric_select_global(), mysqlnd_ms_dump_servers().
PECL/mysqlnd_ms 1.5 series
1.5.1-stable
- Release date: 06/2013
- Motto/theme: Sharding support, improved transaction support
Note:
This is the current stable series. Use this version in production environments.
The documentation is complete.
1.5.0-alpha
- Release date: 03/2013
- Motto/theme: Sharding support, improved transaction support
Bug fixes
-
Fixed #60605 PHP segmentation fault when mysqlnd_ms is enabled.
-
Setting transaction stickiness disables all load balancing, including automatic failover, for the duration of a transaction. So far connection switches could have happened in the middle of a transaction in multi-master configurations and during automatic failover although transaction monitoring had detected transaction boundaries properly.
-
BC break and bug fix. SQL hints enforcing the use of a specific kind of server (
MYSQLND_MS_MASTER_SWITCH,MYSQLND_MS_SLAVE_SWITCH,MYSQLND_MS_LAST_USED_SWITCH) are ignored for the duration of a transaction of transaction stickiness is enabled and transaction boundaries have been detected properly.This is a change in behaviour. However, it is also a bug fix and a step to align behaviour. If, in previous versions, transaction stickiness, one of the above listed SQL hints and the quality of service filtering was combined it could happened that the SQL hints got ignored. In some case the SQL hints did work, in other cases they did not. The new behaviour is more consistent. SQL hints will always be ignore for the duration of a transaction, if transaction stickiness is enabled.
Please note, transaction boundary detection continues to be based on API call monitoring. SQL commands controlling transactions are not monitored.
-
BC break and bug fix. Calls to mysqlnd_ms_set_qos() will fail when done in the middle of a transaction if transaction stickiness is enabled. Connection switches are not allowed for the duration of a transaction. Changing the quality of service likely results on a different set of servers qualifying for query execution, possibly making it necessary to switch connections. Thus, the call is not allowed in during an active transaction. The quality of server can, however, be changed in between transactions.
Feature changes
-
Introduced the
node_groupfilter. The filter lets you organize servers (master and slaves) into groups. Queries can be directed to a certain group of servers by prefixing the query statement with a SQL hint/comment that contains the groups configured name. Grouping can be used for partitioning and sharding, and also to optimize for local caching. In the case of sharding, a group name can be thought of like a shard key. All queries for a given shard key will be executed on the configured shard. Note: both the client and server must support sharding for sharding to function with mysqlnd_ms. -
Extended configuration file validation during PHP startup (RINIT). An
E_WARNINGlevel error will be thrown if the configuration file can not be read (permissions), is empty, or the file (JSON) could not be parsed. Warnings may appear in log files, which depending on how PHP is configured.Distributions that aim to provide a pre-configured setup, including a configuration file stub, are asked to put
{}into the configuration file to prevent this warning about an invalid configuration file.Further configuration file validation is done when parsing sections upon opening a connection. Please, note that there may still be situations when an invalid plugin configuration file does not lead to proper error messages but a failure to connect.
-
As of PHP 5.5.0, improved support for transaction boundaries detection was added for
mysqli. Themysqliextension has been modified to use the new C API calls of themysqlndlibrary to begin, commit, and rollback a transaction or savepoint. If trx_stickiness is used to enable transaction aware load balancing, the mysqli_begin(), mysqli_commit() and mysqli_rollback() functions will now be monitered by the plugin, to go along with the mysqli_autocommit() function that was already supported. All SQL features to control transactions are also available through the improvedmysqlitransaction control related functions. This means that it is not required to issue SQL statements instead of using API calls. Applications using the appropriate API calls can be load balanced by PECL/mysqlnd_ms in a completely transaction-aware way.Please note,
PDO_MySQLhas not been updated yet to utilize the new mysqlnd API calls. Thus, transaction boundary detection withPDO_MySQLcontinues to be limited to the monitoring by passing inPDO::ATTR_AUTOCOMMITto PDO::setAttribute(). -
Introduced
trx_stickiness=on. This trx_stickiness option differs fromtrx_stickiness=masteras it tries to execute a read-only transaction on a slave, if quality of service (consistency level) allows the use of a slave. Read-only transactions were introduced in MySQL 5.6, and they offer performance gains. -
Query cache support is considered beta if used with the
mysqliAPI. It should work fine with primary copy based clusters. For all other APIs, this feature continues to be called experimental. -
The code examples in the mysqlnd_ms source were updated.
PECL/mysqlnd_ms 1.4 series
1.4.2-stable
- Release date: 08/2012
- Motto/theme: Tweaking based on user feedback
1.4.1-beta
- Release date: 08/2012
- Motto/theme: Tweaking based on user feedback
Bug fixes
-
Fixed build with PHP 5.5
1.4.0-alpha
- Release date: 07/2012
- Motto/theme: Tweaking based on user feedback
Feature changes
-
BC break: Renamed plugin configuration setting
ini_filetoconfig_file. In early versions the plugin configuration file used ini style. Back then the configuration setting was named accordingly. It has now been renamed to reflect the newer file format and to distinguish it from PHP's own ini file (configuration directives file). -
Introduced new default charset setting
server_charsetto allow proper escaping before a connection is opened. This is most useful when using lazy connections, which are a default. -
Introduced
wait_for_gtid_timeoutsetting to throttle slave reads that need session consistency. If global transaction identifier are used and the service level is set to session consistency, the plugin tries to find up-to-date slaves. The slave status check is done by a SQL statement. If nothing else is set, the slave status is checked only one can the search for more up-to-date slaves continues immediately thereafter. Settingwait_for_gtid_timeoutinstructs the plugin to poll a slaves status forwait_for_gtid_timeoutseconds if the first execution of the SQL statement has shown that the slave is not up-to-date yet. The poll will be done once per second. This way, the plugin will wait for slaves to catch up and throttle the client. -
New failover strategy
loop_before_master. By default the plugin does no failover. It is possible to enable automatic failover if a connection attempt fails. Upto version 1.3 onlymasterstrategy existed to failover to a master if a slave connection fails.loop_before_masteris similar but tries all other slaves before attempting to connect to the master if a slave connection fails.The number of attempts can be limited using the
max_retriesoption. Failed hosts can be remembered and skipped in load balancing for the rest of the web request.max_retriesandremember_failedare considered experimental although decent stability is given. Syntax and semantics may change in the future without prior notice.
PECL/mysqlnd_ms 1.3 series
1.3.2-stable
- Release date: 04/2012
- Motto/theme: see 1.3.0-alpha
Bug fixes
-
Fixed problem with multi-master where although in a transaction the queries to the master weren't sticky and were spread all over the masters (RR). Still not sticky for Random. Random_once is not affected.
1.3.1-beta
- Release date: 04/2012
- Motto/theme: see 1.3.0-alpha
Bug fixes
-
Fixed problem with building together with QC.
1.3.0-alpha
- Release date: 04/2012
- Motto/theme: Query caching through quality-of-service concept
The 1.3 series aims to improve the performance of applications and the overall load of an asynchronous MySQL cluster, for example, a MySQL cluster using MySQL Replication. This is done by transparently replacing a slave access with a local cache access, if the application allows it by setting an appropriate quality of service flag. When using MySQL replication a slave can serve stale data. An application using MySQL replication must continue to work correctly with stale data. Given that the application is know to work correctly with stale data, the slave access can transparently be replace with a local cache access.
PECL/mysqlnd_qc serves as a cache
backend. PECL/mysqlnd_qc supports use of various storage locations,
among others main memory, APC and MEMCACHE.
Feature changes
-
Added cache option to quality-of-service (QoS) filter.
-
New configure option
enable-mysqlnd-ms-cache-support -
New constant
MYSQLND_MS_HAVE_CACHE_SUPPORT. -
New constant
MYSQLND_MS_QOS_OPTION_CACHEto be used with mysqlnd_ms_set_qos().
-
New configure option
-
Support for built-in global transaction identifier feature of MySQL 5.6.5-m8 or newer.
PECL/mysqlnd_ms 1.2 series
1.2.1-beta
- Release date: 01/2012
- Motto/theme: see 1.2.0-alpha
Minor test changes.
1.2.0-alpha
- Release date: 11/2011
- Motto/theme: Global Transaction ID injection and quality-of-service concept
In version 1.2 the focus continues to be on supporting MySQL database clusters with asynchronous replication. The plugin tries to make using the cluster introducing a quality-of-service filter which applications can use to define what service quality they need from the cluster. Service levels provided are eventual consistency with optional maximum age/slave slag, session consistency and strong consistency.
Additionally the plugin can do client-side global transaction id injection to make manual master failover easier.
Feature changes
-
Introduced quality-of-service (QoS) filter. Service levels provided by QoS filter:
- eventual consistency, optional option slave lag
- session consistency, optional option GTID
- strong consistency
-
Added the mysqlnd_ms_set_qos() function to set the required connection quality at runtime. The new constants related to mysqlnd_ms_set_qos() are:
-
MYSQLND_MS_QOS_CONSISTENCY_STRONG -
MYSQLND_MS_QOS_CONSISTENCY_SESSION -
MYSQLND_MS_QOS_CONSISTENCY_EVENTUAL -
MYSQLND_MS_QOS_OPTION_GTID -
MYSQLND_MS_QOS_OPTION_AGE
-
-
Added client-side global transaction id injection (GTID).
-
New statistics related to GTID:
-
gtid_autocommit_injections_success -
gtid_autocommit_injections_failure -
gtid_commit_injections_success -
gtid_commit_injections_failure -
gtid_implicit_commit_injections_success -
gtid_implicit_commit_injections_failure
-
-
Added mysqlnd_ms_get_last_gtid() to fetch the last global transaction id.
-
Enabled support for multi master without slaves.
PECL/mysqlnd_ms 1.1 series
1.1.0
- Release date: 09/2011
- Motto/theme: Cover replication basics with production quality
The 1.1 and 1.0 series expose a similar feature set. Internally, the 1.1 series has been refactored to plan for future feature additions. A new configuration file format has been introduced, and limitations have been lifted. And the code quality and quality assurance has been improved.
Feature changes
-
Added the (chainable) filter concept:
-
BC break:
mysqlnd_ms_set_user_pick_server()
has been removed. Thehttp://svn.php.net/viewvc/pecl/mysqlnd_ms/trunk/
userfilter has been introduced to replace it. The filter offers similar functionality, but see below for an explanation of the differences.
-
BC break:
mysqlnd_ms_set_user_pick_server()
has been removed. Thehttp://svn.php.net/viewvc/pecl/mysqlnd_ms/trunk/
- New powerful JSON based configuration syntax.
- Lazy connections improved: security relevant, and state changing commands are covered.
- Support for (native) prepared statements.
-
New statistics:
use_master_guess,use_slave_guess.-
BC break: Semantics of statistics changed for
use_slave,use_master. Future changes are likely. Please see, mysqlnd_ms_get_stats().
-
BC break: Semantics of statistics changed for
-
List of broadcasted messages extended by
ssl_set. -
Library calls now monitored to remember settings for lazy connections:
change_user,select_db,set_charset,set_autocommit. -
Introduced
mysqlnd_ms.disable_rw_split. The configuration setting allows using the load balancing and lazy connection functionality independently of read write splitting.
Bug fixes
- Fixed PECL #22724 - Server switching (mysqlnd_ms_query_is_select() case sensitive)
- Fixed PECL #22784 - Using mysql_connect and mysql_select_db did not work
- Fixed PECL #59982 - Unusable extension with --enable-mysqlnd-ms-table-filter. Use of the option is NOT supported. You must not used it. Added note to m4.
- Fixed Bug #60119 - host="localhost" lost in mysqlnd_ms_get_last_used_connection()
The mysqlnd_ms_set_user_pick_server() function was removed, and
replaced in favor of a new user filter. You can no longer set a
callback function using mysqlnd_ms_set_user_pick_server() at
runtime, but instead have to configure it in the plugins configuration file. The user
filter will pass the same arguments to the callback as before.
Therefore, you can continue to use the same procedural function as a callback.callback
It is no longer possible to use static class methods, or class methods of
an object instance, as a callback. Doing so will cause the function
executing a statement handled by the plugin to emit an
E_RECOVERABLE_ERROR level error, which might look like:
"(mysqlnd_ms) Specified callback (picker) is not a valid callback."
Note: this may halt your application.
PECL/mysqlnd_ms 1.0 series
1.0.1-alpha
- Release date: 04/2011
- Motto/theme: bug fix release
1.0.0-alpha
- Release date: 04/2011
- Motto/theme: Cover replication basics to test user feedback
The first release of practical use. It features basic automatic read-write splitting, SQL hints to overrule automatic redirection, load balancing of slave requests, lazy connections, and optional, automatic use of the master after the first write.
The public feature set is close to that of the 1.1 release.
1.0.0-pre-alpha
- Release date: 09/2010
- Motto/theme: Proof of concept
Initial check-in. Essentially a demo of the mysqlnd plugin API.
- Introduction
- Quickstart and Examples
- Concepts
- Installing/Configuring
- Predefined Constants
- Mysqlnd_ms Functions
- mysqlnd_ms_dump_servers — Returns a list of currently configured servers
- mysqlnd_ms_fabric_select_global — Switch to global sharding server for a given table
- mysqlnd_ms_fabric_select_shard — Switch to shard
- mysqlnd_ms_get_last_gtid — Returns the latest global transaction ID
- mysqlnd_ms_get_last_used_connection — Returns an array which describes the last used connection
- mysqlnd_ms_get_stats — Returns query distribution and connection statistics
- mysqlnd_ms_match_wild — Finds whether a table name matches a wildcard pattern or not
- mysqlnd_ms_query_is_select — Find whether to send the query to the master, the slave or the last used MySQL server
- mysqlnd_ms_set_qos — Sets the quality of service needed from the cluster
- mysqlnd_ms_set_user_pick_server — Sets a callback for user-defined read/write splitting
- mysqlnd_ms_xa_begin — Starts a distributed/XA transaction among MySQL servers
- mysqlnd_ms_xa_commit — Commits a distributed/XA transaction among MySQL servers
- mysqlnd_ms_xa_gc — Garbage collects unfinished XA transactions after severe errors
- mysqlnd_ms_xa_rollback — Rolls back a distributed/XA transaction among MySQL servers
- Change History
Mysqlnd query result cache plugin
Introduction
The mysqlnd query result cache plugin adds easy to use client-side query caching to all PHP MySQL extensions using mysqlnd.
As of version PHP 5.3.3 the MySQL native driver for PHP (
mysqlnd)
features an internal plugin C API. C plugins, such as the query cache
plugin, can extend the functionality of
mysqlnd.
Mysqlnd plugins such as the query cache plugin operate transparent from a user perspective. The cache plugin supports all PHP applications and all PHP MySQL extensions ( mysqli, mysql, PDO_MYSQL). It does not change existing APIs.
No significant application changes are required to cache a query. The cache has two operation modes. It will either cache all queries (not recommended) or only those queries marked with a certain SQL hint (recommended).
Key Features
-
Transparent and therefore easy to use
-
supports all PHP MySQL extensions
-
no API changes
-
very little application changes required
-
-
Flexible invalidation strategy
-
Time-to-Live (TTL)
-
user-defined
-
-
Storage with different scope and life-span
-
Default (Hash, process memory)
-
MEMCACHE
-
sqlite
-
user-defined
-
-
Built-in slam defense to prevent cache stampeding.
Limitations
The current 1.0.1 release of PECL mysqlnd_qc does not support PHP 5.4. Version 1.1.0-alpha lifts this limitation.
Prepared statements and unbuffered queries are fully supported.
Thus, the plugin is capable of caching all statements issued
with mysqli or PDO_MySQL, which are
the only two PHP MySQL APIs to offer prepared statement support.
On the name
The shortcut mysqlnd_qc
stands for mysqlnd query cache plugin. The name
was chosen for a quick-and-dirty proof-of-concept. In the beginning
the developers did not expect to continue using the code base.
Sometimes PECL/mysqlnd_qc has also been called
client-side query result set cache.
Quickstart and Examples
Table of Contents
- Architecture and Concepts
- Setup
- Caching queries
- Setting the TTL
- Pattern based caching
- Slam defense
- Finding cache candidates
- Measuring cache efficiency
- Beyond TTL: user-defined storage
The mysqlnd query cache plugin is easy to use. This quickstart will demo typical use-cases, and provide practical advice on getting started.
It is strongly recommended to read the reference sections in addition to the quickstart. It is safe to begin with the quickstart. However, before using the plugin in mission critical environments we urge you to read additionally the background information from the reference sections.
Most of the examples use the mysqli extension because it is the most feature complete PHP MySQL extension. However, the plugin can be used with any PHP MySQL extension that is using the mysqlnd library.
Architecture and Concepts
The query cache plugin is implemented as a PHP extension. It is written in C and operates under the hood of PHP. During the startup of the PHP interpreter, it gets registered as a mysqlnd plugin to replace selected mysqlnd C methods. Hereby, it can change the behaviour of any PHP MySQL extension (mysqli, PDO_MYSQL, mysql) compiled to use the mysqlnd library without changing the extensions API. This makes the plugin compatible with each and every PHP MySQL application. Because existing APIs are not changed, it is almost transparent to use. Please, see the mysqlnd plugin API description for a discussion of the advantages of the plugin architecture and a comparison with proxy based solutions.
Transparent to use
At PHP run time PECL/mysqlnd_qc can proxy queries send from PHP (mysqlnd) to the MySQL server. It then inspects the statement string to find whether it shall cache its results. If so, result set is cached using a storage handler and further executions of the statement are served from the cache for a user-defined period. The Time to Live (TTL) of the cache entry can either be set globally or on a per statement basis.
A statement is either cached if the plugin is instructed to cache all
statements globally using a or, if the query string starts with the SQL hint
(/*qc=on*/). The plugin is capable of caching any
query issued by calling appropriate API calls of any of the existing
PHP MySQL extensions.
Flexible storage: various storage handler
Various storage handler are supported to offer different scopes for cache entries. Different scopes allow for different degrees in sharing cache entries among clients.
-
default(built-in): process memory, scope: process, one or more web requests depending on PHP deployment model used -
APC: shared memory, scope: single server, multiple web requests -
SQLite: memory or file, scope: single server, multiple web requests -
MEMCACHE: main memory, scope: single or multiple server, multiple web requests -
user(built-in): user-defined - any, scope: user-defined - any
Support for the APC, SQLite and
MEMCACHE storage handler has to be enabled at compile time. The
default and user handler are built-in. It is possible
to switch between compiled-in storage handlers on a per query basis at run time.
However, it is recommended to pick one storage handler and use it for all cache entries.
Built-in slam defense to avoid overloading
To avoid overload situations the cache plugin has a built-in slam defense mechanism. If a popular cache entries expires many clients using the cache entries will try to refresh the cache entry. For the duration of the refresh many clients may access the database server concurrently. In the worst case, the database server becomes overloaded and it takes more and more time to refresh the cache entry, which in turn lets more and more clients try to refresh the cache entry. To prevent this from happening the plugin has a slam defense mechanism. If slam defense is enabled and the plugin detects an expired cache entry it extends the life time of the cache entry before it refreshes the cache entry. This way other concurrent accesses to the expired cache entry are still served from the cache for a certain time. The other concurrent accesses to not trigger a concurrent refresh. Ideally, the cache entry gets refreshed by the client which extended the cache entries lifespan before other clients try to refresh the cache and potentially cause an overload situation.
Unique approach to caching
PECL/mysqlnd_qc has a unique approach to caching result sets that is superior to application based cache solutions. Application based solutions first fetch a result set into PHP variables. Then, the PHP variables are serialized for storage in a persistent cache, and then unserialized when fetching. The mysqlnd query cache stores the raw wire protocol data sent from MySQL to PHP in its cache and replays it, if still valid, on a cache hit. This way, it saves an extra serialization step for a cache put that all application based solutions have to do. It can store the raw wire protocol data in the cache without having to serialize into a PHP variable first and deserializing the PHP variable for storing in the cache again.
Setup
The plugin is implemented as a PHP extension. See also the installation instructions to install the » PECL/mysqlnd_qc extension.
Compile or configure the PHP MySQL extension (mysqli, PDO_MYSQL, mysql) that you plan to use with support for the mysqlnd library. PECL/mysqlnd_qc is a plugin for the mysqlnd library. To use the plugin with any of the existing PHP MySQL extensions (APIs), the extension has to use the mysqlnd library.
Then, load the extension into PHP and activate the plugin in the PHP configuration file using the PHP configuration directive named mysqlnd_qc.enable_qc.
Example #1 Enabling the plugin (php.ini)
mysqlnd_qc.enable_qc=1
Caching queries
There are four ways to trigger caching of a query.
- Use of SQL hints on a per query basis
- User supplied callbacks to decide on a per query basis, for example, using mysqlnd_qc_is_select()
- mysqlnd_set_cache_condition() for rule based automatic per query decisions
-
mysqlnd_qc.cache_by_default = 1to cache all queries blindly
Use of SQL hints and
mysqlnd_qc.cache_by_default = 1
are explained below. Please, refer to the function reference on
mysqlnd_qc_is_select() for a description of using a callback and,
mysqlnd_qc_set_cache_condition() on how to set rules for automatic
caching.
A SQL hint is a SQL standards compliant
comment. As a SQL comment it is ignored by the database. A statement is considered
eligible for caching if it either begins with the SQL hint enabling caching
or it is a SELECT statement.
An individual query which shall be cached must begin with the SQL hint
/*qc=on*/. It is recommended to use the PHP constant
MYSQLND_QC_ENABLE_SWITCH
instead of using the string value.
-
not eligible for caching and not cached:
INSERT INTO test(id) VALUES (1) -
not eligible for caching and not cached:
SHOW ENGINES -
eligible for caching but uncached:
SELECT id FROM test -
eligible for caching and cached:
/*qc=on*/SELECT id FROM test
The examples SELECT statement string is prefixed with the
MYSQLND_QC_ENABLE_SWITCH
SQL hint to enable caching of the statement. The SQL hint must be given at
the very beginning of the statement string to enable caching.
Example #1 Using the MYSQLND_QC_ENABLE_SWITCH SQL hint
mysqlnd_qc.enable_qc=1
<?php
/* Connect, create and populate test table */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1), (2)");
/* Will be cached because of the SQL hint */
$start = microtime(true);
$res = $mysqli->query("/*" . MYSQLND_QC_ENABLE_SWITCH . "*/" . "SELECT id FROM test WHERE id = 1");
var_dump($res->fetch_assoc());
$res->free();
printf("Total time uncached query: %.6fs\n", microtime(true) - $start);
/* Cache hit */
$start = microtime(true);
$res = $mysqli->query("/*" . MYSQLND_QC_ENABLE_SWITCH . "*/" . "SELECT id FROM test WHERE id = 1");
var_dump($res->fetch_assoc());
$res->free();
printf("Total time cached query: %.6fs\n", microtime(true) - $start);
?>
The above examples will output something similar to:
array(1) {
["id"]=>
string(1) "1"
}
Total time uncached query: 0.000740s
array(1) {
["id"]=>
string(1) "1"
}
Total time cached query: 0.000098s
If nothing else is configured, as it is the case in the quickstart example,
the plugin will use the built-in default storage handler.
The default storage handler uses process memory to hold a cache entry.
Depending on the PHP deployment model, a PHP process may serve one or more
web requests. Please, consult the web server manual for details.
Details make no difference for the examples given in the quickstart.
The query cache plugin will cache all queries regardless if
the query string begins with the SQL hint which enables caching or not,
if the PHP configuration directive
mysqlnd_qc.cache_by_default
is set to 1. The setting
mysqlnd_qc.cache_by_default
is evaluated by the core of the query cache plugins.
Neither the built-in nor user-defined storage handler can overrule the setting.
The SQL hint /*qc=off*/ can be used to disable caching
of individual queries if
mysqlnd_qc.cache_by_default = 1
It is recommended to use the PHP constant
MYSQLND_QC_DISABLE_SWITCH
instead of using the string value.
Example #2 Using the MYSQLND_QC_DISABLE_SWITCH SQL hint
mysqlnd_qc.enable_qc=1 mysqlnd_qc.cache_by_default=1
<?php
/* Connect, create and populate test table */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1), (2)");
/* Will be cached although no SQL hint is present because of mysqlnd_qc.cache_by_default = 1*/
$res = $mysqli->query("SELECT id FROM test WHERE id = 1");
var_dump($res->fetch_assoc());
$res->free();
$mysqli->query("DELETE FROM test WHERE id = 1");
/* Cache hit - no automatic invalidation and still valid! */
$res = $mysqli->query("SELECT id FROM test WHERE id = 1");
var_dump($res->fetch_assoc());
$res->free();
/* Cache miss - query must not be cached because of the SQL hint */
$res = $mysqli->query("/*" . MYSQLND_QC_DISABLE_SWITCH . "*/SELECT id FROM test WHERE id = 1");
var_dump($res->fetch_assoc());
$res->free();
?>
The above examples will output:
array(1) {
["id"]=>
string(1) "1"
}
array(1) {
["id"]=>
string(1) "1"
}
NULL
PECL/mysqlnd_qc forbids caching of statements for which at least one
column from the statements result set shows no table name in its meta data by default.
This is usually the case for columns originating from SQL functions such as
NOW() or LAST_INSERT_ID(). The policy
aims to prevent pitfalls if caching by default is used.
Example #3 Example showing which type of statements are not cached
mysqlnd_qc.enable_qc=1 mysqlnd_qc.cache_by_default=1
<?php
/* Connect, create and populate test table */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1)");
for ($i = 0; $i < 3; $i++) {
$start = microtime(true);
/* Note: statement will not be cached because of NOW() use */
$res = $mysqli->query("SELECT id, NOW() AS _time FROM test");
$row = $res->fetch_assoc();
/* dump results */
var_dump($row);
printf("Total time: %.6fs\n", microtime(true) - $start);
/* pause one second */
sleep(1);
}
?>
The above examples will output something similar to:
array(2) {
["id"]=>
string(1) "1"
["_time"]=>
string(19) "2012-01-11 15:43:10"
}
Total time: 0.000540s
array(2) {
["id"]=>
string(1) "1"
["_time"]=>
string(19) "2012-01-11 15:43:11"
}
Total time: 0.000555s
array(2) {
["id"]=>
string(1) "1"
["_time"]=>
string(19) "2012-01-11 15:43:12"
}
Total time: 0.000549s
It is possible to enable caching for all statements including those
which has columns in their result set for which MySQL reports no table, such as
the statement from the example. Set
mysqlnd_qc.cache_no_table = 1
to enable caching of such statements. Please, note the difference in the
measured times for the above and below examples.
Example #4 Enabling caching for all statements using the mysqlnd_qc.cache_no_table ini setting
mysqlnd_qc.enable_qc=1 mysqlnd_qc.cache_by_default=1 mysqlnd_qc.cache_no_table=1
<?php
/* Connect, create and populate test table */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1)");
for ($i = 0; $i < 3; $i++) {
$start = microtime(true);
/* Note: statement will not be cached because of NOW() use */
$res = $mysqli->query("SELECT id, NOW() AS _time FROM test");
$row = $res->fetch_assoc();
/* dump results */
var_dump($row);
printf("Total time: %.6fs\n", microtime(true) - $start);
/* pause one second */
sleep(1);
}
?>
The above examples will output something similar to:
array(2) {
["id"]=>
string(1) "1"
["_time"]=>
string(19) "2012-01-11 15:47:45"
}
Total time: 0.000546s
array(2) {
["id"]=>
string(1) "1"
["_time"]=>
string(19) "2012-01-11 15:47:45"
}
Total time: 0.000187s
array(2) {
["id"]=>
string(1) "1"
["_time"]=>
string(19) "2012-01-11 15:47:45"
}
Total time: 0.000167s
Note:
Although
mysqlnd_qc.cache_no_table = 1has been created for use withmysqlnd_qc.cache_by_default = 1it is bound it. The plugin will evaluate themysqlnd_qc.cache_no_tablewhenever a query is to be cached, no matter whether caching has been enabled using a SQL hint or any other measure.
Setting the TTL
The default invalidation strategy of the query cache plugin is Time to Live
(TTL). The built-in storage handlers will use the default
TTL defined by the PHP configuration value
mysqlnd_qc.ttl
unless the query string contains a hint for setting a different
TTL. The TTL is specified in seconds.
By default cache entries expire after 30 seconds
The example sets mysqlnd_qc.ttl=3 to cache
statements for three seconds by default. Every second it updates
a database table record to hold the current time and executes
a SELECT statement to fetch the record from the
database. The SELECT statement is cached for
three seconds because it is prefixed with the SQL hint enabling
caching. The output verifies that the query results are taken
from the cache for the duration of three seconds before they
are refreshed.
Example #1 Setting the TTL with the mysqlnd_qc.ttl ini setting
mysqlnd_qc.enable_qc=1 mysqlnd_qc.ttl=3
<?php
/* Connect, create and populate test table */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id VARCHAR(255))");
for ($i = 0; $i < 7; $i++) {
/* update DB row */
if (!$mysqli->query("DELETE FROM test") ||
!$mysqli->query("INSERT INTO test(id) VALUES (NOW())"))
/* Of course, a real-life script should do better error handling */
die(sprintf("[%d] %s\n", $mysqli->errno, $mysqli->error));
/* select latest row but cache results */
$query = "/*" . MYSQLND_QC_ENABLE_SWITCH . "*/";
$query .= "SELECT id AS _time FROM test";
if (!($res = $mysqli->query($query)) ||
!($row = $res->fetch_assoc()))
{
printf("[%d] %s\n", $mysqli->errno, $mysqli->error);
}
$res->free();
printf("Wall time %s - DB row time %s\n", date("H:i:s"), $row['_time']);
/* pause one second */
sleep(1);
}
?>
The above examples will output something similar to:
Wall time 14:55:59 - DB row time 2012-01-11 14:55:59 Wall time 14:56:00 - DB row time 2012-01-11 14:55:59 Wall time 14:56:01 - DB row time 2012-01-11 14:55:59 Wall time 14:56:02 - DB row time 2012-01-11 14:56:02 Wall time 14:56:03 - DB row time 2012-01-11 14:56:02 Wall time 14:56:04 - DB row time 2012-01-11 14:56:02 Wall time 14:56:05 - DB row time 2012-01-11 14:56:05
As can be seen from the example, any TTL based cache
can serve stale data. Cache entries are not automatically invalidated,
if underlying data changes. Applications using the default
TTL invalidation strategy must be able to work correctly
with stale data.
A user-defined cache storage handler can implement any invalidation strategy to work around this limitation.
The default TTL can be overruled using the SQL hint
/*qc_tt=seconds*/. The SQL hint must be appear immediately
after the SQL hint which enables caching. It is recommended to use the PHP constant
MYSQLND_QC_TTL_SWITCH
instead of using the string value.
Example #2 Setting TTL with SQL hints
<?php
$start = microtime(true);
/* Connect, create and populate test table */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1), (2)");
printf("Default TTL\t: %d seconds\n", ini_get("mysqlnd_qc.ttl"));
/* Will be cached for 2 seconds */
$sql = sprintf("/*%s*//*%s%d*/SELECT id FROM test WHERE id = 1", MYSQLND_QC_ENABLE_SWITCH, MYSQLND_QC_TTL_SWITCH, 2);
$res = $mysqli->query($sql);
var_dump($res->fetch_assoc());
$res->free();
$mysqli->query("DELETE FROM test WHERE id = 1");
sleep(1);
/* Cache hit - no automatic invalidation and still valid! */
$res = $mysqli->query($sql);
var_dump($res->fetch_assoc());
$res->free();
sleep(2);
/* Cache miss - cache entry has expired */
$res = $mysqli->query($sql);
var_dump($res->fetch_assoc());
$res->free();
printf("Script runtime\t: %d seconds\n", microtime(true) - $start);
?>
The above examples will output something similar to:
Default TTL : 30 seconds
array(1) {
["id"]=>
string(1) "1"
}
array(1) {
["id"]=>
string(1) "1"
}
NULL
Script runtime : 3 seconds
Pattern based caching
An application has three options for telling PECL/mysqlnd_qc whether a particular
statement shall be used. The most basic approach is to cache all statements by
setting
mysqlnd_qc.cache_by_default = 1. This approach is often of little
practical value. But it enables users to make a quick estimation about
the maximum performance gains from caching. An application designed to
use a cache may be able to prefix selected statements with the appropriate SQL
hints. However, altering an applications source code may not always be possible
or desired, for example, to avoid problems with software updates. Therefore,
PECL/mysqlnd_qc allows setting a callback which decides if a query is to be
cached.
The callback is installed with the mysqlnd_qc_set_is_select()
function. The callback is given the statement string of every statement
inspected by the plugin. Then, the callback can decide whether to cache
the function. The callback is supposed to return FALSE
if the statement shall not be cached. A return value of TRUE
makes the plugin try to add the statement into the cache. The cache entry
will be given the default TTL (
mysqlnd_qc.ttl). If the callback returns
a numerical value it is used as the TTL instead of the global default.
Example #1 Setting a callback with mysqlnd_qc_set_is_select()
mysqlnd_qc.enable_qc=1 mysqlnd_qc.collect_statistics=1
<?php
/* callback which decides if query is cached */
function is_select($query) {
static $patterns = array(
/* true - use default from mysqlnd_qc.ttl */
"@SELECT\s+.*\s+FROM\s+test@ismU" => true,
/* 3 - use TTL = 3 seconds */
"@SELECT\s+.*\s+FROM\s+news@ismU" => 3
);
/* check if query does match pattern */
foreach ($patterns as $pattern => $ttl) {
if (preg_match($pattern, $query)) {
printf("is_select(%45s): cache\n", $query);
return $ttl;
}
}
printf("is_select(%45s): do not cache\n", $query);
return false;
}
/* install callback */
mysqlnd_qc_set_is_select("is_select");
/* Connect, create and populate test table */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1), (2), (3)");
/* cache put */
$mysqli->query("SELECT id FROM test WHERE id = 1");
/* cache hit */
$mysqli->query("SELECT id FROM test WHERE id = 1");
/* cache put */
$mysqli->query("SELECT * FROM test");
$stats = mysqlnd_qc_get_core_stats();
printf("Cache put: %d\n", $stats['cache_put']);
printf("Cache hit: %d\n", $stats['cache_hit']);
?>
The above examples will output something similar to:
is_select( DROP TABLE IF EXISTS test): do not cache is_select( CREATE TABLE test(id INT)): do not cache is_select( INSERT INTO test(id) VALUES (1), (2), (3)): do not cache is_select( SELECT id FROM test WHERE id = 1): cache is_select( SELECT id FROM test WHERE id = 1): cache is_select( SELECT * FROM test): cache Cache put: 2 Cache hit: 1
The examples callback tests if a statement string matches a pattern.
If this is the case, it either returns TRUE to cache
the statement using the global default TTL or an alternative TTL.
To minimize application changes the callback can put into and registered in an auto prepend file.
Slam defense
A badly designed cache can do more harm than good. In the worst case a cache can increase database server load instead of minimizing it. An overload situation can occur if a highly shared cache entry expires (cache stampeding).
Cache entries are shared and reused to a different degree depending on the storage used. The default storage handler stores cache entries in process memory. Thus, a cache entry can be reused for the life-span of a process. Other PHP processes cannot access it. If Memcache is used, a cache entry can be shared among multiple PHP processes and even among multiple machines, depending on the set up being used.
If a highly shared cache entry stored, for example, in Memcache expires, many clients gets a cache miss. Many client requests can no longer be served from the cache but try to run the underlying query on the database server. Until the cache entry is refreshed, more and more clients contact the database server. In the worst case, a total lost of service is the result.
The overload can be avoided using a storage handler which limits the reuse of cache entries to few clients. Then, at the average, its likely that only a limited number of clients will try to refresh a cache entry concurrently.
Additionally, the built-in slam defense mechanism can and should be used. If
slam defense is activated an expired cache entry is given an extended life time.
The first client getting a cache miss for the expired cache entry tries to
refresh the cache entry within the extended life time. All other clients requesting
the cache entry are temporarily served from the cache although the original
TTL of the cache entry has expired. The other clients will
not experience a cache miss before the extended life time is over.
Example #1 Enabling the slam defense mechanism
mysqlnd_qc.slam_defense=1 mysqlnd_qc.slam_defense_ttl=1
The slam defense mechanism is enabled with the PHP configuration directive
mysqlnd_qc.slam_defense.
The extended life time of a cache entry is set with
mysqlnd_qc.slam_defense_ttl.
The function
mysqlnd_qc_get_core_stats() returns an array of
statistics. The statistics slam_stale_refresh and
slam_stale_hit are incremented if slam defense takes place.
It is not possible to give a one-fits-all recommendation on the slam defense configuration. Users are advised to monitor and test their setup and derive settings accordingly.
Finding cache candidates
A statement should be considered for caching if it is executed often and has a long run time. Cache candidates are found by creating a list of statements sorted by the product of the number of executions multiplied by the statements run time. The function mysqlnd_qc_get_query_trace_log() returns a query log which help with the task.
Collecting a query trace is a slow operation. Thus, it is disabled by default.
The PHP configuration directive
mysqlnd_qc.collect_query_trace
is used to enable it. The functions trace contains one entry for every
query issued before the function is called.
Example #1 Collecting a query trace
mysqlnd_qc.enable_qc=1 mysqlnd_qc.collect_query_trace=1
<?php
/* connect to MySQL */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
/* dummy queries to fill the query trace */
for ($i = 0; $i < 2; $i++) {
$res = $mysqli->query("SELECT 1 AS _one FROM DUAL");
$res->free();
}
/* dump trace */
var_dump(mysqlnd_qc_get_query_trace_log());
?>
The above examples will output:
array(2) {
[0]=>
array(8) {
["query"]=>
string(26) "SELECT 1 AS _one FROM DUAL"
["origin"]=>
string(102) "#0 qc.php(7): mysqli->query('SELECT 1 AS _on...')
#1 {main}"
["run_time"]=>
int(0)
["store_time"]=>
int(25)
["eligible_for_caching"]=>
bool(false)
["no_table"]=>
bool(false)
["was_added"]=>
bool(false)
["was_already_in_cache"]=>
bool(false)
}
[1]=>
array(8) {
["query"]=>
string(26) "SELECT 1 AS _one FROM DUAL"
["origin"]=>
string(102) "#0 qc.php(7): mysqli->query('SELECT 1 AS _on...')
#1 {main}"
["run_time"]=>
int(0)
["store_time"]=>
int(8)
["eligible_for_caching"]=>
bool(false)
["no_table"]=>
bool(false)
["was_added"]=>
bool(false)
["was_already_in_cache"]=>
bool(false)
}
}
Assorted information is given in the trace. Among them
timings and the origin of the query call. The origin property
holds a code backtrace to identify the source of the query.
The depth of the backtrace can be limited with
the PHP configuration directive
mysqlnd_qc.query_trace_bt_depth.
The default depth is 3.
Example #2 Setting the backtrace depth with the mysqlnd_qc.query_trace_bt_depth ini setting
mysqlnd_qc.enable_qc=1 mysqlnd_qc.collect_query_trace=1
<?php
/* connect to MySQL */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1), (2), (3)");
/* dummy queries to fill the query trace */
for ($i = 0; $i < 3; $i++) {
$res = $mysqli->query("SELECT id FROM test WHERE id = " . $mysqli->real_escape_string($i));
$res->free();
}
$trace = mysqlnd_qc_get_query_trace_log();
$summary = array();
foreach ($trace as $entry) {
if (!isset($summary[$entry['query']])) {
$summary[$entry['query']] = array(
"executions" => 1,
"time" => $entry['run_time'] + $entry['store_time'],
);
} else {
$summary[$entry['query']]['executions']++;
$summary[$entry['query']]['time'] += $entry['run_time'] + $entry['store_time'];
}
}
foreach ($summary as $query => $details) {
printf("%45s: %5dms (%dx)\n",
$query, $details['time'], $details['executions']);
}
?>
The above examples will output something similar to:
DROP TABLE IF EXISTS test: 0ms (1x)
CREATE TABLE test(id INT): 0ms (1x)
INSERT INTO test(id) VALUES (1), (2), (3): 0ms (1x)
SELECT id FROM test WHERE id = 0: 25ms (1x)
SELECT id FROM test WHERE id = 1: 10ms (1x)
SELECT id FROM test WHERE id = 2: 9ms (1x)
Measuring cache efficiency
PECL/mysqlnd_qc offers three ways to measure the cache efficiency. The function mysqlnd_qc_get_normalized_query_trace_log() returns statistics aggregated by the normalized query string, mysqlnd_qc_get_cache_info() gives storage handler specific information which includes a list of all cached items, depending on the storage handler. Additionally, the core of PECL/mysqlnd_qc collects high-level summary statistics aggregated per PHP process. The high-level statistics are returned by mysqlnd_qc_get_core_stats().
The functions mysqlnd_qc_get_normalized_query_trace_log() and mysqlnd_qc_get_core_stats() will not collect data unless data collection has been enabled through their corresponding PHP configuration directives. Data collection is disabled by default for performance considerations. It is configurable with the mysqlnd_qc.time_statistics option, which determines if timing information should be collected. Collection of time statistics is enabled by default but only performed if data collection as such has been enabled. Recording time statistics causes extra system calls. In most cases, the benefit of the monitoring outweighs any potential performance penalty of the additional system calls.
Example #1 Collecting statistics data with the mysqlnd_qc.time_statistics ini setting
mysqlnd_qc.enable_qc=1 mysqlnd_qc.collect_statistics=1
<?php
/* connect to MySQL */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1), (2), (3)");
/* dummy queries */
for ($i = 1; $i <= 4; $i++) {
$query = sprintf("/*%s*/SELECT id FROM test WHERE id = %d", MYSQLND_QC_ENABLE_SWITCH, $i % 2);
$res = $mysqli->query($query);
$res->free();
}
var_dump(mysqlnd_qc_get_core_stats());
?>
The above examples will output something similar to:
array(26) {
["cache_hit"]=>
string(1) "2"
["cache_miss"]=>
string(1) "2"
["cache_put"]=>
string(1) "2"
["query_should_cache"]=>
string(1) "4"
["query_should_not_cache"]=>
string(1) "3"
["query_not_cached"]=>
string(1) "3"
["query_could_cache"]=>
string(1) "4"
["query_found_in_cache"]=>
string(1) "2"
["query_uncached_other"]=>
string(1) "0"
["query_uncached_no_table"]=>
string(1) "0"
["query_uncached_no_result"]=>
string(1) "0"
["query_uncached_use_result"]=>
string(1) "0"
["query_aggr_run_time_cache_hit"]=>
string(2) "28"
["query_aggr_run_time_cache_put"]=>
string(3) "900"
["query_aggr_run_time_total"]=>
string(3) "928"
["query_aggr_store_time_cache_hit"]=>
string(2) "14"
["query_aggr_store_time_cache_put"]=>
string(2) "40"
["query_aggr_store_time_total"]=>
string(2) "54"
["receive_bytes_recorded"]=>
string(3) "136"
["receive_bytes_replayed"]=>
string(3) "136"
["send_bytes_recorded"]=>
string(2) "84"
["send_bytes_replayed"]=>
string(2) "84"
["slam_stale_refresh"]=>
string(1) "0"
["slam_stale_hit"]=>
string(1) "0"
["request_counter"]=>
int(1)
["process_hash"]=>
int(1929695233)
}
For a quick overview, call mysqlnd_qc_get_core_stats(). It delivers cache usage, cache timing and traffic related statistics. Values are aggregated on a per process basis for all queries issued by any PHP MySQL API call.
Some storage handler, such as the default handler, can report cache entries, statistics related to the entries and meta data for the underlying query through the mysqlnd_qc_get_cache_info() function. Please note, that the information returned depends on the storage handler. Values are aggregated on a per process basis.
Example #2 Example mysqlnd_qc_get_cache_info() usage
mysqlnd_qc.enable_qc=1
<?php
/* connect to MySQL */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1), (2), (3)");
/* dummy queries to fill the query trace */
for ($i = 1; $i <= 4; $i++) {
$query = sprintf("/*%s*/SELECT id FROM test WHERE id = %d", MYSQLND_QC_ENABLE_SWITCH, $i % 2);
$res = $mysqli->query($query);
$res->free();
}
var_dump(mysqlnd_qc_get_cache_info());
?>
The above examples will output something similar to:
array(4) {
["num_entries"]=>
int(2)
["handler"]=>
string(7) "default"
["handler_version"]=>
string(5) "1.0.0"
["data"]=>
array(2) {
["Localhost via UNIX socket
3306
root
test|/*qc=on*/SELECT id FROM test WHERE id = 1"]=>
array(2) {
["statistics"]=>
array(11) {
["rows"]=>
int(1)
["stored_size"]=>
int(71)
["cache_hits"]=>
int(1)
["run_time"]=>
int(391)
["store_time"]=>
int(27)
["min_run_time"]=>
int(16)
["max_run_time"]=>
int(16)
["min_store_time"]=>
int(8)
["max_store_time"]=>
int(8)
["avg_run_time"]=>
int(8)
["avg_store_time"]=>
int(4)
}
["metadata"]=>
array(1) {
[0]=>
array(8) {
["name"]=>
string(2) "id"
["orig_name"]=>
string(2) "id"
["table"]=>
string(4) "test"
["orig_table"]=>
string(4) "test"
["db"]=>
string(4) "test"
["max_length"]=>
int(1)
["length"]=>
int(11)
["type"]=>
int(3)
}
}
}
["Localhost via UNIX socket
3306
root
test|/*qc=on*/SELECT id FROM test WHERE id = 0"]=>
array(2) {
["statistics"]=>
array(11) {
["rows"]=>
int(0)
["stored_size"]=>
int(65)
["cache_hits"]=>
int(1)
["run_time"]=>
int(299)
["store_time"]=>
int(13)
["min_run_time"]=>
int(11)
["max_run_time"]=>
int(11)
["min_store_time"]=>
int(6)
["max_store_time"]=>
int(6)
["avg_run_time"]=>
int(5)
["avg_store_time"]=>
int(3)
}
["metadata"]=>
array(1) {
[0]=>
array(8) {
["name"]=>
string(2) "id"
["orig_name"]=>
string(2) "id"
["table"]=>
string(4) "test"
["orig_table"]=>
string(4) "test"
["db"]=>
string(4) "test"
["max_length"]=>
int(0)
["length"]=>
int(11)
["type"]=>
int(3)
}
}
}
}
}
It is possible to further break down the granularity of statistics
to the level of the normalized statement string.
The normalized statement string is the statements string with all parameters
replaced with question marks. For example, the two statements
SELECT id FROM test WHERE id = 0 and
SELECT id FROM test WHERE id = 1 are normalized into
SELECT id FROM test WHERE id = ?. Their both
statistics are aggregated into one entry for
SELECT id FROM test WHERE id = ?.
Example #3 Example mysqlnd_qc_get_normalized_query_trace_log() usage
mysqlnd_qc.enable_qc=1 mysqlnd_qc.collect_normalized_query_trace=1
<?php
/* connect to MySQL */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1), (2), (3)");
/* dummy queries to fill the query trace */
for ($i = 1; $i <= 4; $i++) {
$query = sprintf("/*%s*/SELECT id FROM test WHERE id = %d", MYSQLND_QC_ENABLE_SWITCH, $i % 2);
$res = $mysqli->query($query);
$res->free();
}
var_dump(mysqlnd_qc_get_normalized_query_trace_log());
?>
The above examples will output something similar to:
array(4) {
[0]=>
array(9) {
["query"]=>
string(25) "DROP TABLE IF EXISTS test"
["occurences"]=>
int(0)
["eligible_for_caching"]=>
bool(false)
["avg_run_time"]=>
int(0)
["min_run_time"]=>
int(0)
["max_run_time"]=>
int(0)
["avg_store_time"]=>
int(0)
["min_store_time"]=>
int(0)
["max_store_time"]=>
int(0)
}
[1]=>
array(9) {
["query"]=>
string(27) "CREATE TABLE test (id INT )"
["occurences"]=>
int(0)
["eligible_for_caching"]=>
bool(false)
["avg_run_time"]=>
int(0)
["min_run_time"]=>
int(0)
["max_run_time"]=>
int(0)
["avg_store_time"]=>
int(0)
["min_store_time"]=>
int(0)
["max_store_time"]=>
int(0)
}
[2]=>
array(9) {
["query"]=>
string(46) "INSERT INTO test (id ) VALUES (? ), (? ), (? )"
["occurences"]=>
int(0)
["eligible_for_caching"]=>
bool(false)
["avg_run_time"]=>
int(0)
["min_run_time"]=>
int(0)
["max_run_time"]=>
int(0)
["avg_store_time"]=>
int(0)
["min_store_time"]=>
int(0)
["max_store_time"]=>
int(0)
}
[3]=>
array(9) {
["query"]=>
string(31) "SELECT id FROM test WHERE id =?"
["occurences"]=>
int(4)
["eligible_for_caching"]=>
bool(true)
["avg_run_time"]=>
int(179)
["min_run_time"]=>
int(11)
["max_run_time"]=>
int(393)
["avg_store_time"]=>
int(12)
["min_store_time"]=>
int(7)
["max_store_time"]=>
int(25)
}
}
The source distribution of PECL/mysqlnd_qc contains a directory
web/ in which web based monitoring
scripts can be found which give an example how to write a cache monitor.
Please, follow the instructions given in the source.
Since PECL/mysqlnd_qc 1.1.0 it is possible to write statistics into a
log file. Please, see
mysqlnd_qc.collect_statistics_log_file.
Beyond TTL: user-defined storage
The query cache plugin supports the use of user-defined storage handler. User-defined storage handler can use arbitrarily complex invalidation algorithms and support arbitrary storage media.
All user-defined storage handlers have to provide a certain interface. The functions of the user-defined storage handler will be called by the core of the cache plugin. The necessary interface consists of seven public functions. Both procedural and object oriented user-defined storage handler must implement the same set of functions.
Example #1 Using a user-defined storage handler
<?php
/* Enable default caching of all statements */
ini_set("mysqlnd_qc.cache_by_default", 1);
/* Procedural user defined storage handler functions */
$__cache = array();
function get_hash($host_info, $port, $user, $db, $query) {
global $__cache;
printf("\t%s(%d)\n", __FUNCTION__, func_num_args());
return md5(sprintf("%s%s%s%s%s", $host_info, $port, $user, $db, $query));
}
function find_query_in_cache($key) {
global $__cache;
printf("\t%s(%d)\n", __FUNCTION__, func_num_args());
if (isset($__cache[$key])) {
$tmp = $__cache[$key];
if ($tmp["valid_until"] < time()) {
unset($__cache[$key]);
$ret = NULL;
} else {
$ret = $__cache[$key]["data"];
}
} else {
$ret = NULL;
}
return $ret;
}
function return_to_cache($key) {
/*
Called on cache hit after cached data has been processed,
may be used for reference counting
*/
printf("\t%s(%d)\n", __FUNCTION__, func_num_args());
}
function add_query_to_cache_if_not_exists($key, $data, $ttl, $run_time, $store_time, $row_count) {
global $__cache;
printf("\t%s(%d)\n", __FUNCTION__, func_num_args());
$__cache[$key] = array(
"data" => $data,
"row_count" => $row_count,
"valid_until" => time() + $ttl,
"hits" => 0,
"run_time" => $run_time,
"store_time" => $store_time,
"cached_run_times" => array(),
"cached_store_times" => array(),
);
return TRUE;
}
function query_is_select($query) {
printf("\t%s('%s'): ", __FUNCTION__, $query);
$ret = FALSE;
if (stristr($query, "SELECT") !== FALSE) {
/* cache for 5 seconds */
$ret = 5;
}
printf("%s\n", (FALSE === $ret) ? "FALSE" : $ret);
return $ret;
}
function update_query_run_time_stats($key, $run_time, $store_time) {
global $__cache;
printf("\t%s(%d)\n", __FUNCTION__, func_num_args());
if (isset($__cache[$key])) {
$__cache[$key]['hits']++;
$__cache[$key]["cached_run_times"][] = $run_time;
$__cache[$key]["cached_store_times"][] = $store_time;
}
}
function get_stats($key = NULL) {
global $__cache;
printf("\t%s(%d)\n", __FUNCTION__, func_num_args());
if ($key && isset($__cache[$key])) {
$stats = $__cache[$key];
} else {
$stats = array();
foreach ($__cache as $key => $details) {
$stats[$key] = array(
'hits' => $details['hits'],
'bytes' => strlen($details['data']),
'uncached_run_time' => $details['run_time'],
'cached_run_time' => (count($details['cached_run_times']))
? array_sum($details['cached_run_times']) / count($details['cached_run_times'])
: 0,
);
}
}
return $stats;
}
function clear_cache() {
global $__cache;
printf("\t%s(%d)\n", __FUNCTION__, func_num_args());
$__cache = array();
return TRUE;
}
/* Install procedural user-defined storage handler */
if (!mysqlnd_qc_set_user_handlers("get_hash", "find_query_in_cache",
"return_to_cache", "add_query_to_cache_if_not_exists",
"query_is_select", "update_query_run_time_stats", "get_stats", "clear_cache")) {
printf("Failed to install user-defined storage handler\n");
}
/* Connect, create and populate test table */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1), (2)");
printf("\nCache put/cache miss\n");
$res = $mysqli->query("SELECT id FROM test WHERE id = 1");
var_dump($res->fetch_assoc());
$res->free();
/* Delete record to verify we get our data from the cache */
$mysqli->query("DELETE FROM test WHERE id = 1");
printf("\nCache hit\n");
$res = $mysqli->query("SELECT id FROM test WHERE id = 1");
var_dump($res->fetch_assoc());
$res->free();
printf("\nDisplay cache statistics\n");
var_dump(mysqlnd_qc_get_cache_info());
printf("\nFlushing cache, cache put/cache miss");
var_dump(mysqlnd_qc_clear_cache());
$res = $mysqli->query("SELECT id FROM test WHERE id = 1");
var_dump($res->fetch_assoc());
$res->free();
?>
The above examples will output something similar to:
query_is_select('DROP TABLE IF EXISTS test'): FALSE
query_is_select('CREATE TABLE test(id INT)'): FALSE
query_is_select('INSERT INTO test(id) VALUES (1), (2)'): FALSE
Cache put/cache miss
query_is_select('SELECT id FROM test WHERE id = 1'): 5
get_hash(5)
find_query_in_cache(1)
add_query_to_cache_if_not_exists(6)
array(1) {
["id"]=>
string(1) "1"
}
query_is_select('DELETE FROM test WHERE id = 1'): FALSE
Cache hit
query_is_select('SELECT id FROM test WHERE id = 1'): 5
get_hash(5)
find_query_in_cache(1)
return_to_cache(1)
update_query_run_time_stats(3)
array(1) {
["id"]=>
string(1) "1"
}
Display cache statistics
get_stats(0)
array(4) {
["num_entries"]=>
int(1)
["handler"]=>
string(4) "user"
["handler_version"]=>
string(5) "1.0.0"
["data"]=>
array(1) {
["18683c177dc89bb352b29965d112fdaa"]=>
array(4) {
["hits"]=>
int(1)
["bytes"]=>
int(71)
["uncached_run_time"]=>
int(398)
["cached_run_time"]=>
int(4)
}
}
}
Flushing cache, cache put/cache miss clear_cache(0)
bool(true)
query_is_select('SELECT id FROM test WHERE id = 1'): 5
get_hash(5)
find_query_in_cache(1)
add_query_to_cache_if_not_exists(6)
NULL
Installing/Configuring
Table of Contents
Requirements
PHP 5.3.3 or a newer version of PHP.
PECL/mysqlnd_qc is a mysqlnd plugin. It plugs into the mysqlnd library. To use you this plugin with a PHP MySQL extension, the extension (mysqli, mysql, or PDO_MYSQL) must enable the mysqlnd library.
For using the APC storage handler with PECL/mysqlnd_qc 1.0
APC 3.1.3p1-beta or newer.
PECL/mysqlnd_qc 1.2 has been tested with APC 3.1.13-beta.
The APC storage handler cannot be used with a shared build. You cannot use the PHP
configuration directive extension to load the APC and PECL/mysqlnd_qc
extensions if PECL/mysqlnd_qc will use APC as a storage handler. For using
the APC storage handler, you have to statically compile PHP with APC and PECL/mysqlnd_qc
support into PHP.
For using
MEMCACHE storage handler:
Use libmemcache 0.38 or newer.
PECL/mysqlnd_qc 1.2 has been tested with libmemcache 1.4.0.
For using
sqlite storage handler:
Use the sqlite3 extension that
bundled with PHP.
Installation
This » PECL extension is not bundled with PHP.
Information for installing this PECL extension may be found in the manual chapter titled Installation of PECL extensions. Additional information such as new releases, downloads, source files, maintainer information, and a CHANGELOG, can be located here: » https://pecl.php.net/package/mysqlnd_qc
A DLL for this PECL extension is currently unavailable. See also the building on Windows section.
Runtime Configuration
The behaviour of these functions is affected by settings in php.ini.
| Name | Default | Changeable | Changelog |
|---|---|---|---|
| mysqlnd_qc.enable_qc | 1 | PHP_INI_SYSTEM | |
| mysqlnd_qc.ttl | 30 | PHP_INI_ALL | |
| mysqlnd_qc.cache_by_default | 0 | PHP_INI_ALL | |
| mysqlnd_qc.cache_no_table | 0 | PHP_INI_ALL | |
| mysqlnd_qc.use_request_time | 0 | PHP_INI_ALL | |
| mysqlnd_qc.time_statistics | 1 | PHP_INI_ALL | |
| mysqlnd_qc.collect_statistics | 0 | PHP_INI_ALL | |
| mysqlnd_qc.collect_statistics_log_file | /tmp/mysqlnd_qc.stats | PHP_INI_SYSTEM | |
| mysqlnd_qc.collect_query_trace | 0 | PHP_INI_SYSTEM | |
| mysqlnd_qc.query_trace_bt_depth | 3 | PHP_INI_SYSTEM | |
| mysqlnd_qc.collect_normalized_query_trace | 0 | PHP_INI_SYSTEM | |
| mysqlnd_qc.ignore_sql_comments | 1 | PHP_INI_ALL | |
| mysqlnd_qc.slam_defense | 0 | PHP_INI_SYSTEM | |
| mysqlnd_qc.slam_defense_ttl | 30 | PHP_INI_SYSTEM | |
| mysqlnd_qc.std_data_copy | 0 | PHP_INI_SYSTEM | |
| mysqlnd_qc.apc_prefix | qc_ | PHP_INI_ALL | |
| mysqlnd_qc.memc_server | 127.0.0.1 | PHP_INI_ALL | |
| mysqlnd_qc.memc_port | 11211 | PHP_INI_ALL | |
| mysqlnd_qc.sqlite_data_file | :memory: | PHP_INI_ALL |
Here's a short explanation of the configuration directives.
-
mysqlnd_qc.enable_qcinteger -
Enables or disables the plugin. If disabled the extension will not plug into mysqlnd to proxy internal mysqlnd C API calls.
-
mysqlnd_qc.ttlinteger -
Default Time-to-Live (TTL) for cache entries in seconds.
-
mysqlnd_qc.cache_by_defaultinteger -
Cache all queries regardless if they begin with the SQL hint that enables caching of a query or not. Storage handler cannot overrule the setting. It is evaluated by the core of the plugin.
-
mysqlnd_qc.cache_no_tableinteger -
Whether to cache queries with no table name in any of columns meta data of their result set, for example,
SELECT SLEEP(1),SELECT NOW(),SELECT SUBSTRING(). -
mysqlnd_qc.use_request_timeinteger -
Use PHP global request time to avoid
gettimeofday()system calls? If usingAPCstorage handler it should be set to the value ofapc.use_request_time, if not warnings will be generated. -
mysqlnd_qc.time_statisticsinteger -
Collect run time and store time statistics using
gettimeofday()system call? Data will be collected only if you also setmysqlnd_qc.collect_statistics = 1, -
mysqlnd_qc.collect_statisticsinteger -
Collect statistics for mysqlnd_qc_get_core_stats()? Does not influence storage handler statistics! Handler statistics can be an integral part of the handler internal storage format. Therefore, collection of some handler statistics cannot be disabled.
-
mysqlnd_qc.collect_statistics-log-fileinteger -
If
mysqlnd_qc.collect_statisticsandmysqlnd_qc.collect_statistics_log_fileare set, the plugin will dump statistics into the specified log file at every 10th web request during PHP request shutdown. The log file needs to be writable by the web server user.Since 1.1.0.
-
mysqlnd_qc.collect_query_traceinteger -
Collect query back traces?
-
mysqlnd_qc.query_trace_bt_depthinteger -
Maximum depth/level of a query code backtrace.
-
mysqlnd_qc.ignore_sql_commentsinteger -
Whether to remove SQL comments from a query string before hashing it to generate a cache key. Disable if you do not want two statemts such as
SELECT /*my_source_ip=123*/ id FROM testandSELECT /*my_source_ip=456*/ id FROM testto refer to the same cache entry.Since 1.1.0.
-
mysqlnd_qc.slam_defenseinteger -
Activates handler based slam defense (cache stampeding protection) if available. Supported by
DefaultandAPCstorage handler -
mysqlnd_qc.slam_defense_ttlinteger -
TTLfor stale cache entries which are served while another client updates the entries. Supported byAPCstorage handler. -
mysqlnd_qc.collect_normalized_query_traceinteger -
Collect aggregated normalized query traces? The setting has no effect by default. You compile the extension using the define
NORM_QUERY_TRACE_LOGto make use of the setting. -
mysqlnd_qc.std_data_copyinteger -
Default storage handler: copy cached wire data? EXPERIMENTAL – use default setting!
-
mysqlnd_qc.apc_prefixstring -
The
APCstorage handler stores data in theAPCuser cache. The setting sets a prefix to be used for cache entries. -
mysqlnd_qc.memc_serverstring -
MEMCACHEstorage handler: memcache server host. -
mysqlnd_qc.memc_portinteger -
MEMCACHEstorage handler: memcached server port. -
mysqlnd_qc.sqlite_data_filestring -
sqlitestorage handler: data file. Any setting but:memory:may be of little practical value.
Predefined Constants
The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
SQL hint related
Example #1 Using SQL hint constants
The query cache is controlled by SQL hints. SQL hints are used to enable and
disable caching. SQL hints can be used to set the
TTL of a query.
The SQL hints recognized by the query cache can be manually changed at
compile time. This makes it possible to use
mysqlnd_qc in environments in which the default
SQL hints are already taken and interpreted by other systems. Therefore
it is recommended to use the SQL hint string constants instead of
manually adding the default SQL hints to the query string.
<?php
/* Use constants for maximum portability */
$query = "/*" . MYSQLND_QC_ENABLE_SWITCH . "*/SELECT id FROM test";
/* Valid but less portable: default TTL */
$query = "/*qc=on*/SELECT id FROM test";
/* Valid but less portable: per statement TTL */
$query = "/*qc=on*//*qc_ttl=5*/SELECT id FROM test";
printf("MYSQLND_QC_ENABLE_SWITCH: %s\n", MYSQLND_QC_ENABLE_SWITCH);
printf("MYSQLND_QC_DISABLE_SWITCH: %s\n", MYSQLND_QC_DISABLE_SWITCH);
printf("MYSQLND_QC_TTL_SWITCH: %s\n", MYSQLND_QC_TTL_SWITCH);
?>
The above examples will output:
MYSQLND_QC_ENABLE_SWITCH: qc=on MYSQLND_QC_DISABLE_SWITCH: qc=off MYSQLND_QC_TTL_SWITCH: qc_ttl=
-
MYSQLND_QC_ENABLE_SWITCH(string) - SQL hint used to enable caching of a query.
-
MYSQLND_QC_DISABLE_SWITCH(string) -
SQL hint used to disable caching of a query if
mysqlnd_qc.cache_by_default = 1. -
MYSQLND_QC_TTL_SWITCH(string) - SQL hint used to set the TTL of a result set.
-
MYSQLND_QC_SERVER_ID_SWITCH(string) - This SQL hint should not be used in general. It is needed by PECL/mysqlnd_ms to group cache entries for one statement but originating from different physical connections. If the hint is used connection settings such as user, hostname and charset are not considered for generating a cache key of a query. Instead the given value and the query string are used as input to the hashing function that generates the key. PECL/mysqlnd_ms may, if instructed, cache results from MySQL Replication slaves. Because it can hold many connections to the slave the cache key shall not be formed from the user, hostname or other settings that may vary for the various slave connections. Instead, PECL/mysqlnd_ms provides an identifier which refers to the group of slave connections that shall be enabled to share cache entries no matter which physical slave connection was to generate the cache entry. Use of this feature outside of PECL/mysqlnd_ms is not recommended.
mysqlnd_qc_set_cache_condition() related
Example #2 Example mysqlnd_qc_set_cache_condition() usage
The function mysqlnd_qc_set_cache_condition() allows setting conditions for automatic caching of statements which don't begin with the SQL hints necessary to manually enable caching.
<?php
/* Cache all accesses to tables with the name "new%" in schema/database "db_example" for 1 second */
if (!mysqlnd_qc_set_cache_condition(MYSQLND_QC_CONDITION_META_SCHEMA_PATTERN, "db_example.new%", 1)) {
die("Failed to set cache condition!");
}
$mysqli = new mysqli("host", "user", "password", "db_example", "port");
/* cached although no SQL hint given */
$mysqli->query("SELECT id, title FROM news");
$pdo_mysql = new PDO("mysql:host=host;dbname=db_example;port=port", "user", "password");
/* not cached: no SQL hint, no pattern match */
$pdo_mysql->query("SELECT id, title FROM latest_news");
/* cached: TTL 1 second, pattern match */
$pdo_mysql->query("SELECT id, title FROM news");
?>
-
MYSQLND_QC_CONDITION_META_SCHEMA_PATTERN(int) - Used as a parameter of mysqlnd_qc_set_cache_condition() to set conditions for schema based automatic caching.
Other
The plugin version number can be obtained using either
MYSQLND_QC_VERSION, which is the string representation
of the numerical version number, or MYSQLND_QC_VERSION_ID,
which is an integer such as 10000. Developers can calculate the version number
as follows.
| Version (part) | Example |
|---|---|
| Major*10000 | 1*10000 = 10000 |
| Minor*100 | 0*100 = 0 |
| Patch | 0 = 0 |
| MYSQLND_QC_VERSION_ID | 10000 |
-
MYSQLND_QC_VERSION(string) -
Plugin version string, for example,
1.0.0-prototype
.
-
MYSQLND_QC_VERSION_ID(int) - Plugin version number, for example, 10000.
mysqlnd_qc Functions
mysqlnd_qc_clear_cache
(PECL mysqlnd_qc >= 1.0.0)
mysqlnd_qc_clear_cache — Flush all cache contents
Description
Flush all cache contents.
Flushing the cache is a storage handler responsibility.
All built-in storage handler but the
memcache storage
handler support flushing the cache. The
memcache
storage handler cannot flush its cache contents.
User-defined storage handler may or may not support the operation.
Parameters
This function has no parameters.
Return Values
Returns TRUE on success or FALSE on failure.
A return value of
FALSE
indicates that flushing all cache contents has
failed or the operation is not supported by
the active storage handler. Applications must
not expect that calling the function will always
flush the cache.
mysqlnd_qc_get_available_handlers
(PECL mysqlnd_qc >= 1.0.0)
mysqlnd_qc_get_available_handlers — Returns a list of available storage handler
Description
Which storage are available depends on the compile time
configuration of the query cache plugin. The
default storage handler is always available.
All other storage handler must be enabled explicitly when building the
extension.
Parameters
This function has no parameters.
Return Values
Returns an array of available built-in storage handler. For each storage handler the version number and version string is given.
Examples
Example #1 mysqlnd_qc_get_available_handlers() example
<?php
var_dump(mysqlnd_qc_get_available_handlers());
?>
The above examples will output:
array(5) {
["default"]=>
array(2) {
["version"]=>
string(5) "1.0.0"
["version_number"]=>
int(100000)
}
["user"]=>
array(2) {
["version"]=>
string(5) "1.0.0"
["version_number"]=>
int(100000)
}
["APC"]=>
array(2) {
["version"]=>
string(5) "1.0.0"
["version_number"]=>
int(100000)
}
["MEMCACHE"]=>
array(2) {
["version"]=>
string(5) "1.0.0"
["version_number"]=>
int(100000)
}
["sqlite"]=>
array(2) {
["version"]=>
string(5) "1.0.0"
["version_number"]=>
int(100000)
}
}
mysqlnd_qc_get_cache_info
(PECL mysqlnd_qc >= 1.0.0)
mysqlnd_qc_get_cache_info — Returns information on the current handler, the number of cache entries and cache entries, if available
Description
Parameters
This function has no parameters.
Return Values
Returns information on the current handler, the number of cache entries and cache entries, if available. If and what data will be returned for the cache entries is subject to the active storage handler. Storage handler are free to return any data. Storage handler are recommended to return at least the data provided by the default handler, if technically possible.
The scope of the information is the PHP process. Depending on the PHP deployment model a process may serve one or more web requests.
Values are aggregated for all cache activities on a per storage handler basis.
It is not possible to tell how much queries originating from
mysqli, PDO_MySQL or
mysql.API calls have contributed to the aggregated data values. Use
mysqlnd_qc_get_core_stats()
to get timing data aggregated for all storage handlers.
Array of cache information
-
handlerstring -
The active storage handler.
All storage handler. Since 1.0.0.
-
handler_versionstring -
The version of the active storage handler.
All storage handler. Since 1.0.0.
-
num_entriesint -
The number of cache entries. The value depends on the storage handler in use.
The default, APC and SQLite storage handler provide the actual number of cache entries.
The MEMCACHE storage handler always returns
0. MEMCACHE does not support counting the number of cache entries.If a user defined handler is used, the number of entries of the
dataproperty is reported.Since 1.0.0.
-
dataarray -
The version of the active storage handler.
Additional storage handler dependent data on the cache entries. Storage handler are requested to provide similar and comparable information. A user defined storage handler is free to return any data.
Since 1.0.0.
The following information is provided by the default storage handler for the
dataproperty.The
dataproperty holds a hash. The hash is indexed by the internal cache entry identifier of the storage handler. The cache entry identifier is human-readable and contains the query string leading to the cache entry. Please, see also the example below. The following data is given for every cache entry.-
statisticsarray -
Statistics of the cache entry.
Since 1.0.0.
Property Description Version rowsNumber of rows of the cached result set. Since 1.0.0. stored_sizeThe size of the cached result set in bytes. This is the size of the payload. The value is not suited for calculating the total memory consumption of all cache entries including the administrative overhead of the cache entries. Since 1.0.0. cache_hitsHow often the cached entry has been returned. Since 1.0.0. run_timeRun time of the statement to which the cache entry belongs. This is the run time of the uncached statement. It is the time between sending the statement to MySQL receiving a reply from MySQL. Run time saved by using the query cache plugin can be calculated like this: cache_hits * ((run_time - avg_run_time) + (store_time - avg_store_time)).Since 1.0.0. store_timeStore time of the statements result set to which the cache entry belongs. This is the time it took to fetch and store the results of the uncached statement. Since 1.0.0. min_run_timeMinimum run time of the cached statement. How long it took to find the statement in the cache. Since 1.0.0. min_store_timeMinimum store time of the cached statement. The time taken for fetching the cached result set from the storage medium and decoding Since 1.0.0. avg_run_timeAverage run time of the cached statement. Since 1.0.0. avg_store_timeAverage store time of the cached statement. Since 1.0.0. max_run_timeAverage run time of the cached statement. Since 1.0.0. max_store_timeAverage store time of the cached statement. Since 1.0.0. valid_untilTimestamp when the cache entry expires. Since 1.1.0. -
metadataarray -
Metadata of the cache entry. This is the metadata provided by MySQL together with the result set of the statement in question. Different versions of the MySQL server may return different metadata. Unlike with some of the PHP MySQL extensions no attempt is made to hide MySQL server version dependencies and version details from the caller. Please, refer to the MySQL C API documentation that belongs to the MySQL server in use for further details.
The metadata list contains one entry for every column.
Since 1.0.0.
Property Description Version nameThe field name. Depending on the MySQL version this may be the fields alias name. Since 1.0.0. org_nameThe field name. Since 1.0.0. tableThe table name. If an alias name was used for the table, this usually holds the alias name. Since 1.0.0. org_tableThe table name. Since 1.0.0. dbThe database/schema name. Since 1.0.0. max_lengthThe maximum width of the field. Details may vary by MySQL server version. Since 1.0.0. lengthThe width of the field. Details may vary by MySQL server version. Since 1.0.0. typeThe data type of the field. Details may vary by the MySQL server in use. This is the MySQL C API type constants value. It is recommended to use type constants provided by the mysqliextension to test for its meaning. You should not test for certain type values by comparing with certain numbers.Since 1.0.0.
The APC storage handler returns the same information for the
dataproperty but nometadata. Themetadataof a cache entry is set toNULL.The MEMCACHE storage handler does not fill the
dataproperty. Statistics are not available on a per cache entry basis with the MEMCACHE storage handler.A user defined storage handler is free to provide any data.
-
Examples
Example #1 mysqlnd_qc_get_cache_info() example
The example shows the output from the built-in default storage handler. Other storage handler may report different data.
<?php
/* Populate the cache, e.g. using mysqli */
$mysqli = new mysqli("host", "user", "password", "schema");
$mysqli->query("/*" . MYSQLND_QC_ENABLE_SWITCH . "*/SELECT id FROM test");
/* Display cache information */
var_dump(mysqlnd_qc_get_cache_info());
?>
The above examples will output:
array(4) {
["num_entries"]=>
int(1)
["handler"]=>
string(7) "default"
["handler_version"]=>
string(5) "1.0.0"
["data"]=>
array(1) {
["Localhost via UNIX socket 3306 user schema|/*qc=on*/SELECT id FROM test"]=>
array(2) {
["statistics"]=>
array(11) {
["rows"]=>
int(6)
["stored_size"]=>
int(101)
["cache_hits"]=>
int(0)
["run_time"]=>
int(471)
["store_time"]=>
int(27)
["min_run_time"]=>
int(0)
["max_run_time"]=>
int(0)
["min_store_time"]=>
int(0)
["max_store_time"]=>
int(0)
["avg_run_time"]=>
int(0)
["avg_store_time"]=>
int(0)
}
["metadata"]=>
array(1) {
[0]=>
array(8) {
["name"]=>
string(2) "id"
["orig_name"]=>
string(2) "id"
["table"]=>
string(4) "test"
["orig_table"]=>
string(4) "test"
["db"]=>
string(4) "schema"
["max_length"]=>
int(1)
["length"]=>
int(11)
["type"]=>
int(3)
}
}
}
}
}
mysqlnd_qc_get_core_stats
(PECL mysqlnd_qc >= 1.0.0)
mysqlnd_qc_get_core_stats — Statistics collected by the core of the query cache
Description
Returns an array of statistics collected by the core of the cache plugin. The same data fields will be reported for any storage handler because the data is collected by the core.
The
PHP configuration setting
mysqlnd_qc.collect_statistics
controls the collection of statistics. The collection of statistics
is disabled by default for performance reasons.
Disabling the collection of statistics will also disable the collection
of time related statistics.
The
PHP configuration setting
mysqlnd_qc.collect_time_statistics controls the
collection of time related statistics.
The scope of the core statistics is the
PHP process.
Depending on your deployment model a
PHP process may handle one or multiple requests.
Statistics are aggregated for all cache entries and all storage handler.
It is not possible
to tell how much queries originating from
mysqli,
PDO_MySQL or
mysql API calls have
contributed to the aggregated data values.
Parameters
This function has no parameters.
Return Values
Array of core statistics
| Statistic | Description | Version |
|---|---|---|
cache_hit
|
Statement is considered cacheable and cached data has been reused. Statement is considered cacheable and a cache miss happened but the statement got cached by someone else while we process it and thus we can fetch the result from the refreshed cache. | Since 1.0.0. |
cache_miss
|
Statement is considered cacheable...
|
Since 1.0.0. |
cache_put
|
Statement is considered cacheable and has been added to the cache.
Take care when calculating derived statistics. Storage handler
with a storage life time beyond process scope may report
cache_put = 0 together with
cache_hit > 0, if another process has filled
the cache. You may want to use
num_entries from
mysqlnd_qc_get_cache_info() if the handler
supports it (
default,
APC).
|
Since 1.0.0. |
query_should_cache
|
Statement is considered cacheable based on query string analysis.
The statement may or may not be added to the cache. See also
cache_put.
|
Since 1.0.0. |
query_should_not_cache
|
Statement is considered not cacheable based on query string analysis. | Since 1.0.0. |
query_not_cached
|
Statement is considered not cacheable or it is considered cachable but the storage handler has not returned a hash key for it. | Since 1.0.0. |
query_could_cache
|
Statement is considered cacheable...
|
Since 1.0.0. |
query_found_in_cache
|
Statement is considered cacheable and we have found it in the cache but we have not replayed the cached data yet and we have not send the result set to the client yet. This is not considered a cache hit because the client might not fetch the result or the cached data may be faulty. | Since 1.0.0. |
query_uncached_other
|
Statement is considered cacheable and it may or may not be in the cache already but either replaying cached data has failed, no result set is available or some other error has happened. | |
query_uncached_no_table
|
Statement has not been cached because the result set has at least
one column which has no table name in its meta data. An example of
such a query is
SELECT SLEEP(1). To cache those
statements you have to change default value of the PHP configuration directive
mysqlnd_qc.cache_no_table and set
mysqlnd_qc.cache_no_table = 1. Often, it is not
desired to cache such statements.
|
Since 1.0.0. |
query_uncached_use_result
|
Statement would have been cached if a buffered result set
had been used. The situation is also considered as a cache miss and
cache_miss will be incremented as well.
|
Since 1.0.0. |
query_aggr_run_time_cache_hit
|
Aggregated run time (ms) of all cached queries.
Cached queries are those which have incremented
cache_hit.
|
Since 1.0.0. |
query_aggr_run_time_cache_put
|
Aggregated run time (ms) of all uncached queries that
have been put into the cache. See also
cache_put.
|
Since 1.0.0. |
query_aggr_run_time_total
|
Aggregated run time (ms) of all uncached and cached queries that have been inspected and executed by the query cache. | Since 1.0.0. |
query_aggr_store_time_cache_hit
|
Aggregated store time (ms) of all cached queries.
Cached queries are those which have incremented
cache_hit.
|
Since 1.0.0. |
query_aggr_store_time_cache_put
|
Aggregated store time (
ms) of all uncached queries that
have been put into the cache. See also
cache_put.
|
Since 1.0.0. |
query_aggr_store_time_total
|
Aggregated store time (ms) of all uncached and cached queries that have been inspected and executed by the query cache. | Since 1.0.0. |
receive_bytes_recorded
|
Recorded incoming network traffic (
bytes) send from MySQL to PHP.
The traffic may or may not have been added to the cache. The
traffic is the total for all queries regardless if cached or not.
|
Since 1.0.0. |
receive_bytes_replayed
|
Network traffic replayed during cache. This is the total amount of incoming traffic saved because of the usage of the query cache plugin. | Since 1.0.0. |
send_bytes_recorded
|
Recorded outgoing network traffic (
bytes) send from MySQL to PHP.
The traffic may or may not have been added to the cache. The
traffic is the total for all queries regardless if cached or not.
|
Since 1.0.0. |
send_bytes_replayed
|
Network traffic replayed during cache. This is the total amount of outgoing traffic saved because of the usage of the query cache plugin. | Since 1.0.0. |
slam_stale_refresh
|
Number of cache misses which triggered serving stale data until the client causing the cache miss has refreshed the cache entry. | Since 1.0.0. |
slam_stale_hit
|
Number of cache hits while a stale cache entry gets refreshed. | Since 1.0.0. |
Examples
Example #1 mysqlnd_qc_get_core_stats() example
<?php
/* Enable collection of statistics - default: disabled */
ini_set("mysqlnd_qc.collect_statistics", 1);
/* Enable collection of all timing related statistics -
default: enabled but overruled by mysqlnd_qc.collect_statistics = 0 */
ini_set("mysqlnd_qc.collect_time_statistics", 1);
/* Populate the cache, e.g. using mysqli */
$mysqli = new mysqli('host', 'user', 'password', 'schema');
/* Cache miss and cache put */
$mysqli->query("/*qc=on*/SELECT id FROM test");
/* Cache hit */
$mysqli->query("/*qc=on*/SELECT id FROM test");
/* Display core statistics */
var_dump(mysqlnd_qc_get_core_stats());
?>
The above examples will output:
array(26) {
["cache_hit"]=>
string(1) "1"
["cache_miss"]=>
string(1) "1"
["cache_put"]=>
string(1) "1"
["query_should_cache"]=>
string(1) "2"
["query_should_not_cache"]=>
string(1) "0"
["query_not_cached"]=>
string(1) "0"
["query_could_cache"]=>
string(1) "2"
["query_found_in_cache"]=>
string(1) "1"
["query_uncached_other"]=>
string(1) "0"
["query_uncached_no_table"]=>
string(1) "0"
["query_uncached_no_result"]=>
string(1) "0"
["query_uncached_use_result"]=>
string(1) "0"
["query_aggr_run_time_cache_hit"]=>
string(1) "4"
["query_aggr_run_time_cache_put"]=>
string(3) "395"
["query_aggr_run_time_total"]=>
string(3) "399"
["query_aggr_store_time_cache_hit"]=>
string(1) "2"
["query_aggr_store_time_cache_put"]=>
string(1) "8"
["query_aggr_store_time_total"]=>
string(2) "10"
["receive_bytes_recorded"]=>
string(2) "65"
["receive_bytes_replayed"]=>
string(2) "65"
["send_bytes_recorded"]=>
string(2) "29"
["send_bytes_replayed"]=>
string(2) "29"
["slam_stale_refresh"]=>
string(1) "0"
["slam_stale_hit"]=>
string(1) "0"
["request_counter"]=>
int(1)
["process_hash"]=>
int(3547549858)
}
See Also
- Runtime configuration
- mysqlnd_qc.collect_statistics
- mysqlnd_qc.time_statistics
- mysqlnd_qc_get_cache_info() - Returns information on the current handler, the number of cache entries and cache entries, if available
mysqlnd_qc_get_normalized_query_trace_log
(PECL mysqlnd_qc >= 1.0.0)
mysqlnd_qc_get_normalized_query_trace_log — Returns a normalized query trace log for each query inspected by the query cache
Description
Returns a normalized query trace log for each query inspected by the query cache.
The collection of the trace log is disabled by default. To collect
the trace log you have to set the PHP configuration directive
mysqlnd_qc.collect_normalized_query_trace to
1
Entries in the trace log are grouped by the normalized query statement.
The normalized query statement is the query statement with all statement
parameter values being replaced with a question mark. For example, the two
statements SELECT id FROM test WHERE id = 1 and
SELECT id FROM test WHERE id = 2 are normalized as
SELECT id FROM test WHERE id = ?. Whenever a statement
is inspected by the query cache which matches the normalized statement pattern,
its statistics are grouped by the normalized statement string.
Parameters
This function has no parameters.
Return Values
An array of query log. Every list entry contains the normalized query stringand further detail information.
| Key | Description |
|---|---|
query
|
Normalized statement string. |
occurences
|
How many statements have matched the normalized statement string in addition to the one which has created the log entry. The value is zero if a statement has been normalized, its normalized representation has been added to the log but no further queries inspected by PECL/mysqlnd_qc have the same normalized statement string. |
eligible_for_caching
|
Whether the statement could be cached. An statement eligible for caching has not necessarily been cached. It not possible to tell for sure if or how many cached statement have contributed to the aggregated normalized statement log entry. However, comparing the minimum and average run time one can make an educated guess. |
avg_run_time
|
The average run time of all queries contributing to the query log entry. The run time is the time between sending the query statement to MySQL and receiving an answer from MySQL. |
avg_store_time
|
The average store time of all queries contributing to the query log entry. The store time is the time needed to fetch a statements result set from the server to the client and, storing it on the client. |
min_run_time
|
The minimum run time of all queries contributing to the query log entry. |
min_store_time
|
The minimum store time of all queries contributing to the query log entry. |
max_run_time
|
The maximum run time of all queries contributing to the query log entry. |
max_store_time
|
The maximum store time of all queries contributing to the query log entry. |
Examples
Example #1 mysqlnd_qc_get_normalized_query_trace_log() example
mysqlnd_qc.collect_normalized_query_trace=1
<?php
/* Connect, create and populate test table */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1), (2)");
/* not cached */
$res = $mysqli->query("SELECT id FROM test WHERE id = 1");
var_dump($res->fetch_assoc());
$res->free();
/* cache put */
$res = $mysqli->query("/*" . MYSQLND_QC_ENABLE_SWITCH . "*/" . "SELECT id FROM test WHERE id = 2");
var_dump($res->fetch_assoc());
$res->free();
/* cache hit */
$res = $mysqli->query("/*" . MYSQLND_QC_ENABLE_SWITCH . "*/" . "SELECT id FROM test WHERE id = 2");
var_dump($res->fetch_assoc());
$res->free();
var_dump(mysqlnd_qc_get_normalized_query_trace_log());
?>
The above examples will output:
array(1) {
["id"]=>
string(1) "1"
}
array(1) {
["id"]=>
string(1) "2"
}
array(1) {
["id"]=>
string(1) "2"
}
array(4) {
[0]=>
array(9) {
["query"]=>
string(25) "DROP TABLE IF EXISTS test"
["occurences"]=>
int(0)
["eligible_for_caching"]=>
bool(false)
["avg_run_time"]=>
int(0)
["min_run_time"]=>
int(0)
["max_run_time"]=>
int(0)
["avg_store_time"]=>
int(0)
["min_store_time"]=>
int(0)
["max_store_time"]=>
int(0)
}
[1]=>
array(9) {
["query"]=>
string(27) "CREATE TABLE test (id INT )"
["occurences"]=>
int(0)
["eligible_for_caching"]=>
bool(false)
["avg_run_time"]=>
int(0)
["min_run_time"]=>
int(0)
["max_run_time"]=>
int(0)
["avg_store_time"]=>
int(0)
["min_store_time"]=>
int(0)
["max_store_time"]=>
int(0)
}
[2]=>
array(9) {
["query"]=>
string(40) "INSERT INTO test (id ) VALUES (? ), (? )"
["occurences"]=>
int(0)
["eligible_for_caching"]=>
bool(false)
["avg_run_time"]=>
int(0)
["min_run_time"]=>
int(0)
["max_run_time"]=>
int(0)
["avg_store_time"]=>
int(0)
["min_store_time"]=>
int(0)
["max_store_time"]=>
int(0)
}
[3]=>
array(9) {
["query"]=>
string(31) "SELECT id FROM test WHERE id =?"
["occurences"]=>
int(2)
["eligible_for_caching"]=>
bool(true)
["avg_run_time"]=>
int(159)
["min_run_time"]=>
int(12)
["max_run_time"]=>
int(307)
["avg_store_time"]=>
int(10)
["min_store_time"]=>
int(8)
["max_store_time"]=>
int(13)
}
}
See Also
- Runtime configuration
- mysqlnd_qc.collect_normalized_query_trace
- mysqlnd_qc.time_statistics
- mysqlnd_qc_get_query_trace_log() - Returns a backtrace for each query inspected by the query cache
mysqlnd_qc_get_query_trace_log
(PECL mysqlnd_qc >= 1.0.0)
mysqlnd_qc_get_query_trace_log — Returns a backtrace for each query inspected by the query cache
Description
Returns a backtrace for each query inspected by the query cache.
The collection of the backtrace is disabled by default. To collect
the backtrace you have to set the PHP configuration directive
mysqlnd_qc.collect_query_trace to
1
The maximum depth of the backtrace is limited to the depth set
with the PHP configuration directive
mysqlnd_qc.query_trace_bt_depth.
Parameters
This function has no parameters.
Return Values
An array of query backtrace. Every list entry contains the query string, a backtrace and further detail information.
| Key | Description |
|---|---|
query
|
Query string. |
origin
|
Code backtrace. |
run_time
|
Query run time in milliseconds. The collection of
all times and the necessary
gettimeofday
system calls can be disabled by setting the PHP configuration
directive
mysqlnd_qc.time_statistics to
0
|
store_time
|
Query result set store time in milliseconds. The collection of
all times and the necessary
gettimeofday
system calls can be disabled by setting the PHP configuration
directive
mysqlnd_qc.time_statistics to
0
|
eligible_for_caching
|
TRUE if query is cacheable otherwise
FALSE.
|
no_table
|
TRUE if the query has generated a result
set and at least one column from the result set has no table
name set in its metadata. This is usually the case with
queries which one probably do not want to cache such as
SELECT SLEEP(1). By default any such query
will not be added to the cache. See also PHP configuration directive
mysqlnd_qc.cache_no_table.
|
was_added
|
TRUE if the query result has been put into
the cache, otherwise
FALSE.
|
was_already_in_cache
|
TRUE if the query result would have been
added to the cache if it was not already in the cache (cache hit).
Otherwise
FALSE.
|
Examples
Example #1 mysqlnd_qc_get_query_trace_log() example
mysqlnd_qc.collect_query_trace=1
<?php
/* Connect, create and populate test table */
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1), (2)");
/* not cached */
$res = $mysqli->query("SELECT id FROM test WHERE id = 1");
var_dump($res->fetch_assoc());
$res->free();
/* cache put */
$res = $mysqli->query("/*" . MYSQLND_QC_ENABLE_SWITCH . "*/" . "SELECT id FROM test WHERE id = 2");
var_dump($res->fetch_assoc());
$res->free();
/* cache hit */
$res = $mysqli->query("/*" . MYSQLND_QC_ENABLE_SWITCH . "*/" . "SELECT id FROM test WHERE id = 2");
var_dump($res->fetch_assoc());
$res->free();
var_dump(mysqlnd_qc_get_query_trace_log());
?>
The above examples will output:
array(1) {
["id"]=>
string(1) "1"
}
array(1) {
["id"]=>
string(1) "2"
}
array(1) {
["id"]=>
string(1) "2"
}
array(6) {
[0]=>
array(8) {
["query"]=>
string(25) "DROP TABLE IF EXISTS test"
["origin"]=>
string(102) "#0 qc.php(4): mysqli->query('DROP TABLE IF E...')
#1 {main}"
["run_time"]=>
int(0)
["store_time"]=>
int(0)
["eligible_for_caching"]=>
bool(false)
["no_table"]=>
bool(false)
["was_added"]=>
bool(false)
["was_already_in_cache"]=>
bool(false)
}
[1]=>
array(8) {
["query"]=>
string(25) "CREATE TABLE test(id INT)"
["origin"]=>
string(102) "#0 qc.php(5): mysqli->query('CREATE TABLE te...')
#1 {main}"
["run_time"]=>
int(0)
["store_time"]=>
int(0)
["eligible_for_caching"]=>
bool(false)
["no_table"]=>
bool(false)
["was_added"]=>
bool(false)
["was_already_in_cache"]=>
bool(false)
}
[2]=>
array(8) {
["query"]=>
string(36) "INSERT INTO test(id) VALUES (1), (2)"
["origin"]=>
string(102) "#0 qc.php(6): mysqli->query('INSERT INTO tes...')
#1 {main}"
["run_time"]=>
int(0)
["store_time"]=>
int(0)
["eligible_for_caching"]=>
bool(false)
["no_table"]=>
bool(false)
["was_added"]=>
bool(false)
["was_already_in_cache"]=>
bool(false)
}
[3]=>
array(8) {
["query"]=>
string(32) "SELECT id FROM test WHERE id = 1"
["origin"]=>
string(102) "#0 qc.php(9): mysqli->query('SELECT id FROM ...')
#1 {main}"
["run_time"]=>
int(0)
["store_time"]=>
int(25)
["eligible_for_caching"]=>
bool(false)
["no_table"]=>
bool(false)
["was_added"]=>
bool(false)
["was_already_in_cache"]=>
bool(false)
}
[4]=>
array(8) {
["query"]=>
string(41) "/*qc=on*/SELECT id FROM test WHERE id = 2"
["origin"]=>
string(103) "#0 qc.php(14): mysqli->query('/*qc=on*/SELECT...')
#1 {main}"
["run_time"]=>
int(311)
["store_time"]=>
int(13)
["eligible_for_caching"]=>
bool(true)
["no_table"]=>
bool(false)
["was_added"]=>
bool(true)
["was_already_in_cache"]=>
bool(false)
}
[5]=>
array(8) {
["query"]=>
string(41) "/*qc=on*/SELECT id FROM test WHERE id = 2"
["origin"]=>
string(103) "#0 qc.php(19): mysqli->query('/*qc=on*/SELECT...')
#1 {main}"
["run_time"]=>
int(13)
["store_time"]=>
int(8)
["eligible_for_caching"]=>
bool(true)
["no_table"]=>
bool(false)
["was_added"]=>
bool(false)
["was_already_in_cache"]=>
bool(true)
}
}
See Also
- Runtime configuration
- mysqlnd_qc.collect_query_trace
- mysqlnd_qc.query_trace_bt_depth
- mysqlnd_qc.time_statistics
- mysqlnd_qc.cache_no_table
- mysqlnd_qc_get_normalized_query_trace_log() - Returns a normalized query trace log for each query inspected by the query cache
mysqlnd_qc_set_cache_condition
(PECL mysqlnd_qc >= 1.1.0)
mysqlnd_qc_set_cache_condition — Set conditions for automatic caching
Description
$condition_type
,
mixed
$condition
,
mixed
$condition_option
) : boolSets a condition for automatic caching of statements which do not contain the necessary SQL hints to enable caching of them.
Parameters
-
condition_type -
Type of the condition. The only allowed value is
MYSQLND_QC_CONDITION_META_SCHEMA_PATTERN. -
condition -
Parameter for the condition set with
condition_type. Parameter type and structure depend oncondition_typeIf
condition_typeequalsMYSQLND_QC_CONDITION_META_SCHEMA_PATTERNconditionmust be a string. The string sets a pattern. Statements are cached if table and database meta data entry of their result sets match the pattern. The pattern is checked for a match with thedbandorg_tablemeta data entries provided by the underlying MySQL client server library. Please, check the MySQL Reference manual for details about the two entries. Thedbandorg_tablevalues are concatenated with a dot (.) before matched againstcondition. Pattern matching supports the wildcards%and_. The wildcard%will match one or many arbitrary characters._will match one arbitrary character. The escape symbol is backslash. -
condition_option -
Option for
condition. Type and structure depend oncondition_type.If
condition_typeequalsMYSQLND_QC_CONDITION_META_SCHEMA_PATTERNcondition_optionsis the TTL to be used.
Examples
Example #1 mysqlnd_qc_set_cache_condition() example
<?php
/* Cache all accesses to tables with the name "new%" in schema/database "db_example" for 1 second */
if (!mysqlnd_qc_set_cache_condition(MYSQLND_QC_CONDITION_META_SCHEMA_PATTERN, "db_example.new%", 1)) {
die("Failed to set cache condition!");
}
$mysqli = new mysqli("host", "user", "password", "db_example", "port");
/* cached although no SQL hint given */
$mysqli->query("SELECT id, title FROM news");
$pdo_mysql = new PDO("mysql:host=host;dbname=db_example;port=port", "user", "password");
/* not cached: no SQL hint, no pattern match */
$pdo_mysql->query("SELECT id, title FROM latest_news");
/* cached: TTL 1 second, pattern match */
$pdo_mysql->query("SELECT id, title FROM news");
?>
Return Values
Returns TRUE on success or FALSE on FAILURE.
mysqlnd_qc_set_is_select
(PECL mysqlnd_qc >= 1.0.0)
mysqlnd_qc_set_is_select — Installs a callback which decides whether a statement is cached
Description
Installs a callback which decides whether a statement is cached.
There are several ways of hinting PELC/mysqlnd_qc to cache a query.
By default, PECL/mysqlnd_qc attempts to cache a if caching of all statements
is enabled or the query string begins with a certain SQL hint.
The plugin internally calls a function named is_select()
to find out. This internal function can be replaced with a user-defined callback.
Then, the user-defined callback is responsible to decide whether the plugin
attempts to cache a statement. Because the internal function is replaced
with the callback, the callback gains full control. The callback is free
to ignore the configuration setting mysqlnd_qc.cache_by_default
and SQL hints.
The callback is invoked for every statement inspected by the plugin.
It is given the statements string as a parameter. The callback returns
FALSE if the statement shall not be cached. It returns TRUE to
make the plugin attempt to cache the statements result set, if any.
A so-created cache entry is given the default TTL set with the
PHP configuration directive mysqlnd_qc.ttl.
If a different TTL shall be used, the callback returns a numeric
value to be used as the TTL.
The internal is_select function is part of the internal
cache storage handler interface. Thus, a user-defined storage handler
offers the same capabilities.
Parameters
This function has no parameters.
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 mysqlnd_qc_set_is_select() example
<?php
/* callback which decides if query is cached */
function is_select($query) {
static $patterns = array(
/* true - use default from mysqlnd_qc.ttl */
"@SELECT\s+.*\s+FROM\s+test@ismU" => true,
/* 3 - use TTL = 3 seconds */
"@SELECT\s+.*\s+FROM\s+news@ismU" => 3
);
/* check if query does match pattern */
foreach ($patterns as $pattern => $ttl) {
if (preg_match($pattern, $query)) {
printf("is_select(%45s): cache\n", $query);
return $ttl;
}
}
printf("is_select(%45s): do not cache\n", $query);
return false;
}
mysqlnd_qc_set_is_select("is_select");
/* Connect, create and populate test table */
$mysqli = new mysqli("host", "user", "password", "schema");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1), (2), (3)");
/* cache put */
$mysqli->query("SELECT id FROM test WHERE id = 1");
/* cache hit */
$mysqli->query("SELECT id FROM test WHERE id = 1");
/* cache put */
$mysqli->query("SELECT * FROM test");
?>
The above examples will output:
is_select( DROP TABLE IF EXISTS test): do not cache is_select( CREATE TABLE test(id INT)): do not cache is_select( INSERT INTO test(id) VALUES (1), (2), (3)): do not cache is_select( SELECT id FROM test WHERE id = 1): cache is_select( SELECT id FROM test WHERE id = 1): cache is_select( SELECT * FROM test): cache
See Also
- Runtime configuration
- mysqlnd_qc.ttl
- mysqlnd_qc.cache_by_default
- mysqlnd_qc_set_user_handlers() - Sets the callback functions for a user-defined procedural storage handler
mysqlnd_qc_set_storage_handler
(PECL mysqlnd_qc >= 1.0.0)
mysqlnd_qc_set_storage_handler — Change current storage handler
Description
$handler
) : bool
Sets the storage handler used by the query cache. A list of available
storage handler can be obtained from
mysqlnd_qc_get_available_handlers().
Which storage are available depends on the compile time
configuration of the query cache plugin. The
default storage handler is always available.
All other storage handler must be enabled explicitly when building the
extension.
Parameters
-
handler -
Handler can be of type string representing the name of a built-in storage handler or an object of type
mysqlnd_qc_handler_default. The names of the built-in storage handler aredefault,APC,MEMCACHE,sqlite.
Return Values
Returns TRUE on success or FALSE on failure.
If changing the storage handler fails a catchable fatal error will be thrown. The query cache cannot operate if the previous storage handler has been shutdown but no new storage handler has been installed.
Examples
Example #1 mysqlnd_qc_set_storage_handler() example
The example shows the output from the built-in default storage handler. Other storage handler may report different data.
<?php
var_dump(mysqlnd_qc_set_storage_handler("memcache"));
if (true === mysqlnd_qc_set_storage_handler("default"))
printf("Default storage handler activated");
/* Catchable fatal error */
var_dump(mysqlnd_qc_set_storage_handler("unknown"));
?>
The above examples will output:
bool(true) Default storage handler activated Catchable fatal error: mysqlnd_qc_set_storage_handler(): Unknown handler 'unknown' in (file) on line (line)
See Also
- Installation
- mysqlnd_qc_get_available_handlers() - Returns a list of available storage handler
mysqlnd_qc_set_user_handlers
(PECL mysqlnd_qc >= 1.0.0)
mysqlnd_qc_set_user_handlers — Sets the callback functions for a user-defined procedural storage handler
Description
$get_hash
,
string
$find_query_in_cache
,
string
$return_to_cache
,
string
$add_query_to_cache_if_not_exists
,
string
$query_is_select
,
string
$update_query_run_time_stats
,
string
$get_stats
,
string
$clear_cache
) : boolSets the callback functions for a user-defined procedural storage handler.
Parameters
-
get_hash -
Name of the user function implementing the storage handler
get_hashfunctionality. -
find_query_in_cache -
Name of the user function implementing the storage handler
find_in_cachefunctionality. -
return_to_cache -
Name of the user function implementing the storage handler
return_to_cachefunctionality. -
add_query_to_cache_if_not_exists -
Name of the user function implementing the storage handler
add_query_to_cache_if_not_existsfunctionality. -
query_is_select -
Name of the user function implementing the storage handler
query_is_selectfunctionality. -
update_query_run_time_stats -
Name of the user function implementing the storage handler
update_query_run_time_statsfunctionality. -
get_stats -
Name of the user function implementing the storage handler
get_statsfunctionality. -
clear_cache -
Name of the user function implementing the storage handler
clear_cachefunctionality.
Return Values
Returns TRUE on success or FALSE on FAILURE.
Table of Contents
- mysqlnd_qc_clear_cache — Flush all cache contents
- mysqlnd_qc_get_available_handlers — Returns a list of available storage handler
- mysqlnd_qc_get_cache_info — Returns information on the current handler, the number of cache entries and cache entries, if available
- mysqlnd_qc_get_core_stats — Statistics collected by the core of the query cache
- mysqlnd_qc_get_normalized_query_trace_log — Returns a normalized query trace log for each query inspected by the query cache
- mysqlnd_qc_get_query_trace_log — Returns a backtrace for each query inspected by the query cache
- mysqlnd_qc_set_cache_condition — Set conditions for automatic caching
- mysqlnd_qc_set_is_select — Installs a callback which decides whether a statement is cached
- mysqlnd_qc_set_storage_handler — Change current storage handler
- mysqlnd_qc_set_user_handlers — Sets the callback functions for a user-defined procedural storage handler
Change History
Table of Contents
This change history is a high level summary of selected changes that may impact applications and/or break backwards compatibility.
See also the CHANGES file in the source distribution for a complete list of changes.
PECL/mysqlnd_qc 1.2 series
1.2.0 - alpha
- Release date: 03/2013
- Motto/theme: PHP 5.5 compatibility
Feature changes
-
Update build for PHP 5.5 (Credits: Remi Collet)
-
APC storage handler update
- Fix build for APC 3.1.13-beta and trunk
-
Introduced
MYSQLND_QC_VERSIONandMYSQLND_QC_VERSION_ID.
PECL/mysqlnd_qc 1.1 series
1.1.0 - stable
- Release date: 04/2012
- Motto/theme: PHP 5.4 compatibility, schema pattern based caching and mysqlnd_ms support
1.1.0 - beta
- Release date: 04/2012
- Motto/theme: PHP 5.4 compatibility, schema pattern based caching and mysqlnd_ms support
1.1.0 - alpha
- Release date: 04/2012
- Motto/theme: PHP 5.4 compatibility, schema pattern based caching and mysqlnd_ms support
Feature changes
-
APC storage handler update
- Fix build for APC 3.1.9+
- Note: Use of the APC storage handler is currently not recommended due to stability issues of APC itself.
-
New PHP configuration directives
-
mysqlnd_qc.collect_statistics_log_file. Aggregated cache statistics log file written after every 10th request served by the PHP process. -
mysqlnd_qc.ignore_sql_comments. Control whether SQL comments are ignored for cache key hash generation.
-
-
New constants and SQL hints
-
MYSQLND_QC_SERVER_ID_SWITCHallows grouping of cache entries from different physical connections. This is needed by PECL/mysqlnd_ms. -
MYSQLND_QC_CONDITION_META_SCHEMA_PATTERNto be used with mysqlnd_qc_set_cache_condition().
-
-
New function mysqlnd_qc_set_cache_condition() for built-in schema pattern based caching. Likely to support a wider range of conditions in the future.
-
Report
valid_untiltimestamp for cache entries of the default handler through mysqlnd_qc_get_cache_info(). -
Include charset number for cache entry hashing. This should prevent serving result sets which have the wrong charset.
API change: get_hash_key expects new "charsetnr" (int) parameter after "port".
-
API change: changing is_select() signature from bool is_select() to mixed is_select(). Mixed can be either boolean or array(long ttl, string server_id). This is needed by PECL/mysqlnd_ms.
Other
-
Support acting as a cache backend for PECL/mysqlnd_ms 1.3.0-beta or later to transparently replace MySQL Replication slave reads with cache accesses, if the user explicitly allows.
Bug fixes
- Fixed Bug #59959 (config.m4, wrong library - 64bit memcached handler builds) (Credits: Remi Collet)
PECL/mysqlnd_qc 1.0 series
1.0.1-stable
- Release date: 12/2010
- Motto/theme: Prepared statement support
Added support for Prepared statements and unbuffered queries.
1.0.0-beta
- Release date: 07/2010
- Motto/theme: TTL-based cache with various storage options (Memcache, APC, SQLite, user-defined)
Initial public release of the transparent TTL-based query result cache. Flexible storage of cached results. Various storage media supported.
- Introduction
- Quickstart and Examples
- Installing/Configuring
- Predefined Constants
- mysqlnd_qc Functions
- mysqlnd_qc_clear_cache — Flush all cache contents
- mysqlnd_qc_get_available_handlers — Returns a list of available storage handler
- mysqlnd_qc_get_cache_info — Returns information on the current handler, the number of cache entries and cache entries, if available
- mysqlnd_qc_get_core_stats — Statistics collected by the core of the query cache
- mysqlnd_qc_get_normalized_query_trace_log — Returns a normalized query trace log for each query inspected by the query cache
- mysqlnd_qc_get_query_trace_log — Returns a backtrace for each query inspected by the query cache
- mysqlnd_qc_set_cache_condition — Set conditions for automatic caching
- mysqlnd_qc_set_is_select — Installs a callback which decides whether a statement is cached
- mysqlnd_qc_set_storage_handler — Change current storage handler
- mysqlnd_qc_set_user_handlers — Sets the callback functions for a user-defined procedural storage handler
- Change History
Mysqlnd user handler plugin
Introduction
The mysqlnd user handler plugin (mysqlnd_uh)
allows users to set hooks for most internal calls of the
MySQL native driver for PHP
(mysqlnd).
Mysqlnd and its plugins, including PECL/mysqlnd_uh, operate on a layer
beneath the PHP MySQL extensions. A mysqlnd plugin can be considered
as a proxy between the PHP MySQL extensions and the MySQL server
as part of the PHP executable on the client-side. Because the plugins
operates on their own layer below the PHP MySQL extensions,
they can monitor and change application actions without requiring
application changes. If the
PHP MySQL extensions (mysqli,
mysql,
PDO_MYSQL) are compiled to
use mysqlnd this can be used for:
-
Monitoring
-
Queries executed by any of the PHP MySQL extensions
-
Prepared statements executing by any of the PHP MySQL extensions
-
-
Auditing
-
Detection of database usage
-
SQL injection protection using black and white lists
-
-
Assorted
-
Load Balancing connections
-
The MySQL native driver for PHP (mysqlnd) features an internal plugin C API. C plugins, such as the mysqlnd user handler plugin, can extend the functionality of mysqlnd. PECL/mysqlnd_uh makes parts of the internal plugin C API available to the PHP user for plugin development with PHP.
Note: Status
The mysqlnd user handler plugin is in alpha status. Take appropriate care before using it in production environments.
Security considerations
PECL/mysqlnd_uh gives users access to MySQL user names, MySQL password
used by any of the PHP MySQL extensions to connect to MySQL.
It allows monitoring of all queries and prepared statements exposing
the statement string to the user. Therefore, the extension should be
installed with care. The PHP_INI_SYSTEM configuration setting
mysqlnd_uh.enable
can be used to prevent users from hooking mysqlnd calls.
Code obfuscators and similar technologies are not suitable to prevent monitoring of mysqlnd library activities if PECL/mysqlnd_uh is made available and the user can install a proxy, for example, using auto_prepend_file.
Documentation note
Many of the mysqlnd_uh functions are briefly described because
the mysqli extension is
a thin abstraction layer on top of the MySQL C API that
the mysqlnd library provides. Therefore,
the corresponding mysqli documentation
(along with the MySQL reference manual) can be consulted
to receive more information about a particular function.
On the name
The shortcut mysqlnd_uh stands for
mysqlnd user handler, and has been the name
since early development.
Quickstart and Examples
Table of Contents
The mysqlnd user handler plugin can be understood as a client-side proxy
for all PHP MySQL extensions (mysqli,
mysql,
PDO_MYSQL), if they are compiled to
use the mysqlnd library. The
extensions use the mysqlnd library internally, at the C
level, to communicate with the MySQL server. PECL/mysqlnd_uh
allows it to hook many mysqlnd calls. Therefore,
most activities of the PHP MySQL extensions can be monitored.
Because monitoring happens at the level of the library, at a layer below the application, it is possible to monitor applications without changing them.
On the C level, the mysqlnd library is structured in modules
or classes. The extension hooks almost all methods of the mysqlnd
internal connection class and exposes them through the
user space class MysqlndUhConnection. Some few methods of
the mysqlnd internal statement class are made available
to the PHP user with the class MysqlndUhPreparedStatement.
By subclassing the classes MysqlndUhConnection and
MysqlndUhPreparedStatement users get access to
mysqlnd internal function calls.
Note:
The internal
mysqlndfunction calls are not designed to be exposed to the PHP user. Manipulating their activities may cause PHP to crash or leak memory. Often, this is not considered a bug. Please, keep in mind that you are accessing C library functions through PHP which are expected to take certain actions, which you may not be able to emulate in user space. Therefore, it is strongly recommended to always call the parent method implementation when subclassing MysqlndUhConnection or MysqlndUhPreparedStatement. To prevent the worst case, the extension performs some sanity checks. Please, see also the Mysqlnd_uh Configure Options.
Setup
The plugin is implemented as a PHP extension. See the installation instructions to install the » PECL/mysqlnd_uh extension. Then, load the extension into PHP and activate the plugin in the PHP configuration file using the PHP configuration directive named mysqlnd_uh.enable. The below example shows the default settings of the extension.
Example #1 Enabling the plugin (php.ini)
mysqlnd_uh.enable=1 mysqlnd_uh.report_wrong_types=1
How it works
This describes the background and inner workings of the mysqlnd_uh extension.
Two classes are provided by the extension: MysqlndUhConnection
and MysqlndUhPreparedStatement. MysqlndUhConnection lets
you access almost all methods of the mysqlnd
internal connection class. The latter exposes some selected
methods of the mysqlnd internal statement class.
For example, MysqlndUhConnection::connect() maps to
the mysqlnd library C function
mysqlnd_conn__connect.
As a mysqlnd plugin, the PECL/mysqlnd_uh extension replaces mysqlnd
library C functions with its own functions. Whenever a
PHP MySQL extension compiled to use mysqlnd calls
a mysqlnd function, the functions installed by the plugin are executed
instead of the original mysqlnd ones. For example,
mysqli_connect() invokes mysqlnd_conn__connect,
so the connect function installed by PECL/mysqlnd_uh will be called.
The functions installed by PECL/mysqlnd_uh are the methods of the built-in classes.
The built-in PHP classes and their methods do nothing but call their
mysqlnd C library counterparts, to behave exactly
like the original mysqlnd function they replace.
The code below illustrates in pseudo-code what the extension does.
Example #1 Pseudo-code: what a built-in class does
class MysqlndUhConnection {
public function connect(($conn, $host, $user, $passwd, $db, $port, $socket, $mysql_flags) {
MYSQLND* c_mysqlnd_connection = convert_from_php_to_c($conn);
...
return call_c_function(mysqlnd_conn__connect(c_mysqlnd_connection, ...));
}
}
The build-in classes behave like a transparent proxy. It is possible for you to replace the proxy with your own. This is done by subclassing MysqlndUhConnection or MysqlndUhPreparedStatement to extend the functionality of the proxy, followed by registering a new proxy object. Proxy objects are installed by mysqlnd_uh_set_connection_proxy() and mysqlnd_uh_set_statement_proxy().
Example #2 Installing a proxy
<?php
class proxy extends MysqlndUhConnection {
public function connect($res, $host, $user, $passwd, $db, $port, $socket, $mysql_flags) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::connect($res, $host, $user, $passwd, $db, $port, $socket, $mysql_flags);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
?>
The above example will output:
proxy::connect(array (
0 => NULL,
1 => 'localhost',
2 => 'root',
3 => '',
4 => 'test',
5 => 3306,
6 => NULL,
7 => 131072,
))
proxy::connect returns true
Installing a proxy
The extension provides two built-in classes: MysqlndUhConnection
and MysqlndUhPreparedStatement. The classes are used
for hooking mysqlnd library calls. Their methods correspond
to mysqlnd internal functions. By default they act like
a transparent proxy and do nothing but call their mysqlnd counterparts.
By subclassing the classes you can install your own proxy to monitor mysqlnd.
See also the How it works guide to learn about the inner workings of this extension.
Connection proxies are objects of the type MysqlndUhConnection. Connection proxy objects are installed by mysqlnd_uh_set_connection_proxy(). If you install the built-in class MysqlndUhConnection as a proxy, nothing happens. It behaves like a transparent proxy.
Example #1 Proxy registration, mysqlnd_uh.enable=1
<?php
mysqlnd_uh_set_connection_proxy(new MysqlndUhConnection());
$mysqli = new mysqli("localhost", "root", "", "test");
?>
The PHP_INI_SYSTEM configuration setting
mysqlnd_uh.enable
controls whether a proxy may be set. If disabled, the extension
will throw errors of type E_WARNING
Example #2 Proxy installation disabled
mysqlnd_uh.enable=0
<?php
mysqlnd_uh_set_connection_proxy(new MysqlndUhConnection());
$mysqli = new mysqli("localhost", "root", "", "test");
?>
The above example will output:
PHP Warning: MysqlndUhConnection::__construct(): (Mysqlnd User Handler) The plugin has been disabled by setting the configuration parameter mysqlnd_uh.enabled = false. You must not use any of the base classes in %s on line %d PHP Warning: mysqlnd_uh_set_connection_proxy(): (Mysqlnd User Handler) The plugin has been disabled by setting the configuration parameter mysqlnd_uh.enable = false. The proxy has not been installed in %s on line %d
To monitor mysqlnd, you have to write your own
proxy object subclassing MysqlndUhConnection.
Please, see the function reference for a the list of methods that
can be subclassed. Alternatively, you can use reflection to inspect
the built-in MysqlndUhConnection.
Create a new class proxy. Derive it from the
built-in class MysqlndUhConnection.
Replace the
MysqlndUhConnection::connect().
method. Print out the host parameter value passed to the method.
Make sure that you call the parent implementation of the connect
method. Failing to do so may give unexpected and undesired results, including
memory leaks and crashes.
Register your proxy and open three connections using the PHP MySQL
extensions mysqli,
mysql,
PDO_MYSQL. If the extensions have been
compiled to use the mysqlnd library, the
proxy::connect method will be called three times, once
for each connection opened.
Example #3 Connection proxy
<?php
class proxy extends MysqlndUhConnection {
public function connect($res, $host, $user, $passwd, $db, $port, $socket, $mysql_flags) {
printf("Connection opened to '%s'\n", $host);
/* Always call the parent implementation! */
return parent::connect($res, $host, $user, $passwd, $db, $port, $socket, $mysql_flags);
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysql = mysql_connect("localhost", "root", "");
$pdo = new PDO("mysql:host=localhost;dbname=test", "root", "");
?>
The above example will output:
Connection opened to 'localhost' Connection opened to 'localhost' Connection opened to 'localhost'
The use of prepared statement proxies follows the same pattern: create a proxy object of the type MysqlndUhPreparedStatement and install the proxy using mysqlnd_uh_set_statement_proxy().
Example #4 Prepared statement proxy
<?php
class stmt_proxy extends MysqlndUhPreparedStatement {
public function prepare($res, $query) {
printf("%s(%s)\n", __METHOD__, $query);
return parent::prepare($res, $query);
}
}
mysqlnd_uh_set_statement_proxy(new stmt_proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$stmt = $mysqli->prepare("SELECT 'mysqlnd hacking made easy' AS _msg FROM DUAL");
?>
The above example will output:
stmt_proxy::prepare(SELECT 'mysqlnd hacking made easy' AS _msg FROM DUAL)
Basic query monitoring
Basic monitoring of a query statement is easy with PECL/mysqlnd_uh. Combined with debug_print_backtrace() it can become a powerful tool, for example, to find the origin of certain statement. This may be desired when searching for slow queries but also after database refactoring to find code still accessing deprecated databases or tables. The latter may be a complicated matter to do otherwise, especially if the application uses auto-generated queries.
Example #1 Basic Monitoring
<?php
class conn_proxy extends MysqlndUhConnection {
public function query($res, $query) {
debug_print_backtrace();
return parent::query($res, $query);
}
}
class stmt_proxy extends MysqlndUhPreparedStatement {
public function prepare($res, $query) {
debug_print_backtrace();
return parent::prepare($res, $query);
}
}
mysqlnd_uh_set_connection_proxy(new conn_proxy());
mysqlnd_uh_set_statement_proxy(new stmt_proxy());
printf("Proxies installed...\n");
$pdo = new PDO("mysql:host=localhost;dbname=test", "root", "");
var_dump($pdo->query("SELECT 1 AS _one FROM DUAL")->fetchAll(PDO::FETCH_ASSOC));
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->prepare("SELECT 1 AS _two FROM DUAL");
?>
The above example will output:
#0 conn_proxy->query(Resource id #19, SELECT 1 AS _one FROM DUAL)
#1 PDO->query(SELECT 1 AS _one FROM DUAL) called at [example.php:19]
array(1) {
[0]=>
array(1) {
["_one"]=>
string(1) "1"
}
}
#0 stmt_proxy->prepare(Resource id #753, SELECT 1 AS _two FROM DUAL)
#1 mysqli->prepare(SELECT 1 AS _two FROM DUAL) called at [example.php:22]
For basic query monitoring you should install a connection and a prepared statement
proxy. The connection proxy should subclass MysqlndUhConnection::query().
All database queries not using native prepared statements will call this method.
In the example the query function is invoked by a PDO call.
By default, PDO_MySQL is using prepared statement emulation.
All native prepared statements are prepared with the prepare
method of mysqlnd exported through
MysqlndUhPreparedStatement::prepare(). Subclass
MysqlndUhPreparedStatement and overwrite prepare
for native prepared statement monitoring.
Installing/Configuring
Table of Contents
Requirements
PHP 5.3.3 or later.
It is recommended to use PHP 5.4.0 or later
to get access to the latest mysqlnd features.
The mysqlnd_uh user handler
plugin supports all PHP applications and all available PHP MySQL extensions
(mysqli,
mysql,
PDO_MYSQL).
The PHP MySQL extension must be configured to use
mysqlnd in order to be able
to use the mysqlnd_uh plugin for
mysqlnd.
The alpha versions makes use of some mysqli features.
You must enable mysqli to compile the plugin.
This requirement may be removed in the future. Note, that this requirement
does not restrict you to use the plugin only with mysqli.
You can use the plugin to monitor mysql, mysqli
and PDO_MYSQL.
Installation
Information for installing this PECL extension may be found in the manual chapter titled Installation of PECL extensions. Additional information such as new releases, downloads, source files, maintainer information, and a CHANGELOG, can be located here: » https://pecl.php.net/package/mysqlnd-uh
PECL/mysqlnd_uh is currently not available on Windows.
The source code of the extension makes use of C99
constructs not allowed with PHP Windows builds.
Runtime Configuration
The behaviour of these functions is affected by settings in php.ini.
| Name | Default | Changeable | Changelog |
|---|---|---|---|
| mysqlnd_uh.enable | 1 | PHP_INI_SYSTEM | |
| mysqlnd_uh.report_wrong_types | 1 | PHP_INI_ALL |
Here's a short explanation of the configuration directives.
-
mysqlnd_uh.enableinteger -
Enables or disables the plugin. If set to disabled, the extension will not allow users to plug into mysqlnd to hook mysqlnd calls.
-
mysqlnd_uh.report_wrong_typesinteger -
Whether to report wrong return value types of user hooks as
E_WARNINGlevel errors. This is recommended for detecting errors.
Resource Types
This extension has no resource types defined.
Predefined Constants
The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
Most of the constants refer to details of the MySQL Client Server Protocol. Please, refer to the MySQL reference manual to learn about their meaning. To avoid content duplication, only short descriptions are given.
MysqlndUhConnection::simpleCommand() related
The following constants can be used to detect what command is to be send through MysqlndUhConnection::simpleCommand().
-
MYSQLND_UH_MYSQLND_COM_SLEEP(integer) - MySQL Client Server protocol command: COM_SLEEP.
-
MYSQLND_UH_MYSQLND_COM_QUIT(integer) - MySQL Client Server protocol command: COM_QUIT.
-
MYSQLND_UH_MYSQLND_COM_INIT_DB(integer) - MySQL Client Server protocol command: COM_INIT_DB.
-
MYSQLND_UH_MYSQLND_COM_QUERY(integer) - MySQL Client Server protocol command: COM_QUERY.
-
MYSQLND_UH_MYSQLND_COM_FIELD_LIST(integer) - MySQL Client Server protocol command: COM_FIELD_LIST.
-
MYSQLND_UH_MYSQLND_COM_CREATE_DB(integer) - MySQL Client Server protocol command: COM_CREATE_DB.
-
MYSQLND_UH_MYSQLND_COM_DROP_DB(integer) - MySQL Client Server protocol command: COM_DROP_DB.
-
MYSQLND_UH_MYSQLND_COM_REFRESH(integer) - MySQL Client Server protocol command: COM_REFRESH.
-
MYSQLND_UH_MYSQLND_COM_SHUTDOWN(integer) - MySQL Client Server protocol command: COM_SHUTDOWN.
-
MYSQLND_UH_MYSQLND_COM_STATISTICS(integer) - MySQL Client Server protocol command: COM_STATISTICS.
-
MYSQLND_UH_MYSQLND_COM_PROCESS_INFO(integer) - MySQL Client Server protocol command: COM_PROCESS_INFO.
-
MYSQLND_UH_MYSQLND_COM_CONNECT(integer) - MySQL Client Server protocol command: COM_CONNECT.
-
MYSQLND_UH_MYSQLND_COM_PROCESS_KILL(integer) - MySQL Client Server protocol command: COM_PROCESS_KILL.
-
MYSQLND_UH_MYSQLND_COM_DEBUG(integer) - MySQL Client Server protocol command: COM_DEBUG.
-
MYSQLND_UH_MYSQLND_COM_PING(integer) - MySQL Client Server protocol command: COM_PING.
-
MYSQLND_UH_MYSQLND_COM_TIME(integer) - MySQL Client Server protocol command: COM_TIME.
-
MYSQLND_UH_MYSQLND_COM_DELAYED_INSERT(integer) - MySQL Client Server protocol command: COM_DELAYED_INSERT.
-
MYSQLND_UH_MYSQLND_COM_CHANGE_USER(integer) - MySQL Client Server protocol command: COM_CHANGE_USER.
-
MYSQLND_UH_MYSQLND_COM_BINLOG_DUMP(integer) - MySQL Client Server protocol command: COM_BINLOG_DUMP.
-
MYSQLND_UH_MYSQLND_COM_TABLE_DUMP(integer) - MySQL Client Server protocol command: COM_TABLE_DUMP.
-
MYSQLND_UH_MYSQLND_COM_CONNECT_OUT(integer) - MySQL Client Server protocol command: COM_CONNECT_OUT.
-
MYSQLND_UH_MYSQLND_COM_REGISTER_SLAVED(integer) - MySQL Client Server protocol command: COM_REGISTER_SLAVED.
-
MYSQLND_UH_MYSQLND_COM_STMT_PREPARE(integer) - MySQL Client Server protocol command: COM_STMT_PREPARE.
-
MYSQLND_UH_MYSQLND_COM_STMT_EXECUTE(integer) - MySQL Client Server protocol command: COM_STMT_EXECUTE.
-
MYSQLND_UH_MYSQLND_COM_STMT_SEND_LONG_DATA(integer) - MySQL Client Server protocol command: COM_STMT_SEND_LONG_DATA.
-
MYSQLND_UH_MYSQLND_COM_STMT_CLOSE(integer) - MySQL Client Server protocol command: COM_STMT_CLOSE.
-
MYSQLND_UH_MYSQLND_COM_STMT_RESET(integer) - MySQL Client Server protocol command: COM_STMT_RESET.
-
MYSQLND_UH_MYSQLND_COM_SET_OPTION(integer) - MySQL Client Server protocol command: COM_SET_OPTION.
-
MYSQLND_UH_MYSQLND_COM_STMT_FETCH(integer) - MySQL Client Server protocol command: COM_STMT_FETCH.
-
MYSQLND_UH_MYSQLND_COM_DAEMON(integer) - MySQL Client Server protocol command: COM_DAEMON.
-
MYSQLND_UH_MYSQLND_COM_END(integer) - MySQL Client Server protocol command: COM_END.
The following constants can be used to analyze the ok_packet
argument of MysqlndUhConnection::simpleCommand().
-
MYSQLND_UH_MYSQLND_PROT_GREET_PACKET(integer) - MySQL Client Server protocol packet: greeting.
-
MYSQLND_UH_MYSQLND_PROT_AUTH_PACKET(integer) - MySQL Client Server protocol packet: authentication.
-
MYSQLND_UH_MYSQLND_PROT_OK_PACKET(integer) - MySQL Client Server protocol packet: OK.
-
MYSQLND_UH_MYSQLND_PROT_EOF_PACKET(integer) - MySQL Client Server protocol packet: EOF.
-
MYSQLND_UH_MYSQLND_PROT_CMD_PACKET(integer) - MySQL Client Server protocol packet: command.
-
MYSQLND_UH_MYSQLND_PROT_RSET_HEADER_PACKET(integer) - MySQL Client Server protocol packet: result set header.
-
MYSQLND_UH_MYSQLND_PROT_RSET_FLD_PACKET(integer) - MySQL Client Server protocol packet: resultset field.
-
MYSQLND_UH_MYSQLND_PROT_ROW_PACKET(integer) - MySQL Client Server protocol packet: row.
-
MYSQLND_UH_MYSQLND_PROT_STATS_PACKET(integer) - MySQL Client Server protocol packet: stats.
-
MYSQLND_UH_MYSQLND_PREPARE_RESP_PACKET(integer) - MySQL Client Server protocol packet: prepare response.
-
MYSQLND_UH_MYSQLND_CHG_USER_RESP_PACKET(integer) - MySQL Client Server protocol packet: change user response.
-
MYSQLND_UH_MYSQLND_PROT_LAST(integer) - No practical meaning. Last entry marker of internal C data structure list.
MysqlndUhConnection::close() related
The following constants can be used to detect why a connection has been
closed through MysqlndUhConnection::close().
-
MYSQLND_UH_MYSQLND_CLOSE_EXPLICIT(integer) - User has called mysqlnd to close the connection.
-
MYSQLND_UH_MYSQLND_CLOSE_IMPLICIT(integer) - Implicitly closed, for example, during garbage connection.
-
MYSQLND_UH_MYSQLND_CLOSE_DISCONNECTED(integer) - Connection error.
-
MYSQLND_UH_MYSQLND_CLOSE_LAST(integer) - No practical meaning. Last entry marker of internal C data structure list.
MysqlndUhConnection::setServerOption() related
The following constants can be used to detect which option is set through
MysqlndUhConnection::setServerOption().
-
MYSQLND_UH_SERVER_OPTION_MULTI_STATEMENTS_ON(integer) - Option: enables multi statement support.
-
MYSQLND_UH_SERVER_OPTION_MULTI_STATEMENTS_OFF(integer) - Option: disables multi statement support.
MysqlndUhConnection::setClientOption() related
The following constants can be used to detect which option is set through MysqlndUhConnection::setClientOption().
-
MYSQLND_UH_MYSQLND_OPTION_OPT_CONNECT_TIMEOUT(integer) - Option: connection timeout.
-
MYSQLND_UH_MYSQLND_OPTION_OPT_COMPRESS(integer) - Option: whether the MySQL compressed protocol is to be used.
-
MYSQLND_UH_MYSQLND_OPTION_OPT_NAMED_PIPE(integer) - Option: named pipe to use for connection (Windows).
-
MYSQLND_UH_MYSQLND_OPTION_INIT_COMMAND(integer) - Option: init command to execute upon connect.
-
MYSQLND_UH_MYSQLND_READ_DEFAULT_FILE(integer) - Option: MySQL server default file to read upon connect.
-
MYSQLND_UH_MYSQLND_READ_DEFAULT_GROUP(integer) - Option: MySQL server default file group to read upon connect.
-
MYSQLND_UH_MYSQLND_SET_CHARSET_DIR(integer) - Option: charset description files directory.
-
MYSQLND_UH_MYSQLND_SET_CHARSET_NAME(integer) - Option: charset name.
-
MYSQLND_UH_MYSQLND_OPT_LOCAL_INFILE(integer) -
Option: Whether to allow
LOAD DATA LOCAL INFILEuse. -
MYSQLND_UH_MYSQLND_OPT_PROTOCOL(integer) - Option: supported protocol version.
- Option: shared memory base name for shared memory connections.
-
MYSQLND_UH_MYSQLND_OPT_READ_TIMEOUT(integer) - Option: connection read timeout.
-
MYSQLND_UH_MYSQLND_OPT_WRITE_TIMEOUT(integer) - Option: connection write timeout.
-
MYSQLND_UH_MYSQLND_OPT_USE_RESULT(integer) - Option: unbuffered result sets.
-
MYSQLND_UH_MYSQLND_OPT_USE_REMOTE_CONNECTION(integer) - Embedded server related.
-
MYSQLND_UH_MYSQLND_OPT_USE_EMBEDDED_CONNECTION(integer) - Embedded server related.
-
MYSQLND_UH_MYSQLND_OPT_GUESS_CONNECTION(integer) - TODO
-
MYSQLND_UH_MYSQLND_SET_CLIENT_IP(integer) - TODO
-
MYSQLND_UH_MYSQLND_SECURE_AUTH(integer) - TODO
-
MYSQLND_UH_MYSQLND_REPORT_DATA_TRUNCATION(integer) - Option: Whether to report data truncation.
-
MYSQLND_UH_MYSQLND_OPT_RECONNECT(integer) - Option: Whether to reconnect automatically.
-
MYSQLND_UH_MYSQLND_OPT_SSL_VERIFY_SERVER_CERT(integer) - Option: TODO
-
MYSQLND_UH_MYSQLND_OPT_NET_CMD_BUFFER_SIZE(integer) - Option: mysqlnd network buffer size for commands.
-
MYSQLND_UH_MYSQLND_OPT_NET_READ_BUFFER_SIZE(integer) - Option: mysqlnd network buffer size for reading from the server.
-
MYSQLND_UH_MYSQLND_OPT_SSL_KEY(integer) - Option: SSL key.
-
MYSQLND_UH_MYSQLND_OPT_SSL_CERT(integer) - Option: SSL certificate.
-
MYSQLND_UH_MYSQLND_OPT_SSL_CA(integer) - Option: SSL CA.
-
MYSQLND_UH_MYSQLND_OPT_SSL_CAPATH(integer) - Option: Path to SSL CA.
-
MYSQLND_UH_MYSQLND_OPT_SSL_CIPHER(integer) - Option: SSL cipher.
-
MYSQLND_UH_MYSQLND_OPT_SSL_PASSPHRASE(integer) - Option: SSL passphrase.
-
MYSQLND_UH_SERVER_OPTION_PLUGIN_DIR(integer) - Option: server plugin directory.
-
MYSQLND_UH_SERVER_OPTION_DEFAULT_AUTH(integer) - Option: default authentication method.
-
MYSQLND_UH_SERVER_OPTION_SET_CLIENT_IP(integer) - TODO
-
MYSQLND_UH_MYSQLND_OPT_MAX_ALLOWED_PACKET(integer) -
Option: maximum allowed packet size. Available as of
PHP 5.4.0. -
MYSQLND_UH_MYSQLND_OPT_AUTH_PROTOCOL(integer) -
Option: TODO. Available as of
PHP 5.4.0. -
MYSQLND_UH_MYSQLND_OPT_INT_AND_FLOAT_NATIVE(integer) - Option: make mysqlnd return integer and float columns as long even when using the MySQL Client Server text protocol. Only available with a custom build of mysqlnd.
Other
The plugins version number can be obtained using
MYSQLND_UH_VERSION or
MYSQLND_UH_VERSION_ID.
MYSQLND_UH_VERSION
is the string representation of the numerical version number
MYSQLND_UH_VERSION_ID, which is an integer such as 10000.
Developers can calculate the version number as follows.
| Version (part) | Example |
|---|---|
| Major*10000 | 1*10000 = 10000 |
| Minor*100 | 0*100 = 0 |
| Patch | 0 = 0 |
MYSQLND_UH_VERSION_ID |
10000 |
The MysqlndUhConnection class
(PECL mysqlnd-uh >= 1.0.0-alpha)
Introduction
Class synopsis
$connection
, string $user
, string $password
, string $database
, bool $silent
, int $passwd_len
) : bool$connection
, string $host
, string $use"
, string $password
, string $database
, int $port
, string $socket
, int $mysql_flags
) : bool$connection
, string $query
, string $achtung_wild
, string $par1
) : void$connection
, mysqlnd_statement $mysqlnd_stmt
) : bool$connection
, int $command
, string $arg
, int $ok_packet
, bool $silent
, bool $ignore_upsert_status
) : bool$connection
, int $ok_packet
, bool $silent
, int $command
, bool $ignore_upsert_status
) : bool$connection
, string $key
, string $cert
, string $ca
, string $capath
, string $cipher
) : boolMysqlndUhConnection::changeUser
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::changeUser — Changes the user of the specified mysqlnd database connection
Description
$connection
, string $user
, string $password
, string $database
, bool $silent
, int $passwd_len
) : boolChanges the user of the specified mysqlnd database connection
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
user -
The MySQL user name.
-
password -
The MySQL password.
-
database -
The MySQL database to change to.
-
silent -
Controls if mysqlnd is allowed to emit errors or not.
-
passwd_len -
Length of the MySQL password.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::changeUser() example
<?php
class proxy extends MysqlndUhConnection {
/* Hook mysqlnd's connection::change_user call */
public function changeUser($res, $user, $passwd, $db, $silent, $passwd_len) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::changeUser($res, $user, $passwd, $db, $silent, $passwd_len);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
/* Install proxy/hooks to be used with all future mysqlnd connection */
mysqlnd_uh_set_connection_proxy(new proxy());
/* Create mysqli connection which is using the mysqlnd library */
$mysqli = new mysqli("localhost", "root", "", "test");
/* Example of a user API call which triggers the hooked mysqlnd call */
var_dump($mysqli->change_user("root", "bar", "test"));
?>
The above example will output:
proxy::changeUser(array (
0 => NULL,
1 => 'root',
2 => 'bar',
3 => 'test',
4 => false,
5 => 3,
))
proxy::changeUser returns false
bool(false)
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_change_user() - Changes the user of the specified database connection
MysqlndUhConnection::charsetName
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::charsetName — Returns the default character set for the database connection
Description
$connection
) : stringReturns the default character set for the database connection.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
The default character set.
Examples
Example #1 MysqlndUhConnection::charsetName() example
<?php
class proxy extends MysqlndUhConnection {
public function charsetName($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::charsetName($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
var_dump(mysqli_character_set_name($mysqli));
?>
The above example will output:
proxy::charsetName(array (
0 => NULL,
))
proxy::charsetName returns 'latin1'
string(6) "latin1"
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_character_set_name() - Returns the default character set for the database connection
MysqlndUhConnection::close
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::close — Closes a previously opened database connection
Description
$connection
, int $close_type
) : boolCloses a previously opened database connection.
Note:
Failing to call the parent implementation may cause memory leaks or crash PHP. This is not considered a bug. Please, keep in mind that the
mysqlndlibrary functions have never been designed to be exposed to the user space.
Parameters
-
connection -
The connection to be closed. Do not modify!
-
close_type -
Why the connection is to be closed. The value of
close_typeis one ofMYSQLND_UH_MYSQLND_CLOSE_EXPLICIT,MYSQLND_UH_MYSQLND_CLOSE_IMPLICIT,MYSQLND_UH_MYSQLND_CLOSE_DISCONNECTEDorMYSQLND_UH_MYSQLND_CLOSE_LAST. The latter should never be seen, unless the default behaviour of themysqlndlibrary has been changed by a plugin.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::close() example
<?php
function close_type_to_string($close_type) {
$mapping = array(
MYSQLND_UH_MYSQLND_CLOSE_DISCONNECTED => "MYSQLND_UH_MYSQLND_CLOSE_DISCONNECTED",
MYSQLND_UH_MYSQLND_CLOSE_EXPLICIT => "MYSQLND_UH_MYSQLND_CLOSE_EXPLICIT",
MYSQLND_UH_MYSQLND_CLOSE_IMPLICIT => "MYSQLND_UH_MYSQLND_CLOSE_IMPLICIT",
MYSQLND_UH_MYSQLND_CLOSE_LAST => "MYSQLND_UH_MYSQLND_CLOSE_IMPLICIT"
);
return (isset($mapping[$close_type])) ? $mapping[$close_type] : 'unknown';
}
class proxy extends MysqlndUhConnection {
public function close($res, $close_type) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
printf("close_type = %s\n", close_type_to_string($close_type));
/* WARNING: you must call the parent */
$ret = parent::close($res, $close_type);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->close();
?>
The above example will output:
proxy::close(array (
0 => NULL,
1 => 0,
))
close_type = MYSQLND_UH_MYSQLND_CLOSE_EXPLICIT
proxy::close returns true
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_close() - Closes a previously opened database connection
- mysql_close() - Close MySQL connection
MysqlndUhConnection::connect
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::connect — Open a new connection to the MySQL server
Description
$connection
, string $host
, string $use"
, string $password
, string $database
, int $port
, string $socket
, int $mysql_flags
) : boolOpen a new connection to the MySQL server.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
host -
Can be either a host name or an IP address. Passing the NULL value or the string "localhost" to this parameter, the local host is assumed. When possible, pipes will be used instead of the TCP/IP protocol.
-
user -
The MySQL user name.
-
password -
If not provided or
NULL, the MySQL server will attempt to authenticate the user against those user records which have no password only. This allows one username to be used with different permissions (depending on if a password as provided or not). -
database -
If provided will specify the default database to be used when performing queries.
-
port -
Specifies the port number to attempt to connect to the MySQL server.
-
socket -
Specifies the socket or named pipe that should be used. If
NULL, mysqlnd will default to/tmp/mysql.sock. -
mysql_flags -
Connection options.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::connect() example
<?php
class proxy extends MysqlndUhConnection {
public function connect($res, $host, $user, $passwd, $db, $port, $socket, $mysql_flags) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::connect($res, $host, $user, $passwd, $db, $port, $socket, $mysql_flags);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
?>
The above example will output:
proxy::connect(array (
0 => NULL,
1 => 'localhost',
2 => 'root',
3 => '',
4 => 'test',
5 => 3306,
6 => NULL,
7 => 131072,
))
proxy::connect returns true
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_connect() - Alias of mysqli::__construct
- mysql_connect() - Open a connection to a MySQL Server
MysqlndUhConnection::__construct
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::__construct — The __construct purpose
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
MysqlndUhConnection::endPSession
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::endPSession — End a persistent connection
Description
$connection
) : boolEnd a persistent connection
This function is currently not documented; only its argument list is available.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::endPSession() example
<?php
class proxy extends MysqlndUhConnection {
public function endPSession($conn) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::endPSession($conn);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("p:localhost", "root", "", "test");
$mysqli->close();
?>
The above example will output:
proxy::endPSession(array (
0 => NULL,
))
proxy::endPSession returns true
MysqlndUhConnection::escapeString
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::escapeString — Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection
Description
$connection
, string $escape_string
) : stringEscapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection.
Parameters
-
MYSQLND_UH_RES_MYSQLND_NAME -
Mysqlnd connection handle. Do not modify!
-
escape_string -
The string to be escaped.
Return Values
The escaped string.
Examples
Example #1 MysqlndUhConnection::escapeString() example
<?php
class proxy extends MysqlndUhConnection {
public function escapeString($res, $string) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::escapeString($res, $string);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->set_charset("latin1");
$mysqli->real_escape_string("test0'test");
?>
The above example will output:
proxy::escapeString(array (
0 => NULL,
1 => 'test0\'test',
))
proxy::escapeString returns 'test0\\\'test'
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_real_escape_string() - Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection
- mysql_real_escape_string() - Escapes special characters in a string for use in an SQL statement
MysqlndUhConnection::getAffectedRows
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getAffectedRows — Gets the number of affected rows in a previous MySQL operation
Description
$connection
) : intGets the number of affected rows in a previous MySQL operation.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Number of affected rows.
Examples
Example #1 MysqlndUhConnection::getAffectedRows() example
<?php
class proxy extends MysqlndUhConnection {
public function getAffectedRows($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getAffectedRows($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT)");
$mysqli->query("INSERT INTO test(id) VALUES (1)");
var_dump($mysqli->affected_rows);
?>
The above example will output:
proxy::getAffectedRows(array (
0 => NULL,
))
proxy::getAffectedRows returns 1
int(1)
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_affected_rows() - Gets the number of affected rows in a previous MySQL operation
- mysql_affected_rows() - Get number of affected rows in previous MySQL operation
MysqlndUhConnection::getErrorNumber
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getErrorNumber — Returns the error code for the most recent function call
Description
$connection
) : intReturns the error code for the most recent function call.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Error code for the most recent function call.
Examples
MysqlndUhConnection::getErrorNumber() is not only executed after the invocation of a user space API call which maps directly to it but also called internally.
Example #1 MysqlndUhConnection::getErrorNumber() example
<?php
class proxy extends MysqlndUhConnection {
public function getErrorNumber($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getErrorNumber($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
printf("connect...\n");
$mysqli = new mysqli("localhost", "root", "", "test");
printf("query...\n");
$mysqli->query("PLEASE_LET_THIS_BE_INVALID_SQL");
printf("errno...\n");
var_dump($mysqli->errno);
printf("close...\n");
$mysqli->close();
?>
The above example will output:
connect...
proxy::getErrorNumber(array (
0 => NULL,
))
proxy::getErrorNumber returns 0
query...
errno...
proxy::getErrorNumber(array (
0 => NULL,
))
proxy::getErrorNumber returns 1064
int(1064)
close...
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- MysqlndUhConnection::getErrorString() - Returns a string description of the last error
- mysqli_errno() - Returns the error code for the most recent function call
- mysql_errno() - Returns the numerical value of the error message from previous MySQL operation
MysqlndUhConnection::getErrorString
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getErrorString — Returns a string description of the last error
Description
$connection
) : stringReturns a string description of the last error.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Error string for the most recent function call.
Examples
MysqlndUhConnection::getErrorString() is not only executed after the invocation of a user space API call which maps directly to it but also called internally.
Example #1 MysqlndUhConnection::getErrorString() example
<?php
class proxy extends MysqlndUhConnection {
public function getErrorString($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getErrorString($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
printf("connect...\n");
$mysqli = new mysqli("localhost", "root", "", "test");
printf("query...\n");
$mysqli->query("WILL_I_EVER_LEARN_SQL?");
printf("errno...\n");
var_dump($mysqli->error);
printf("close...\n");
$mysqli->close();
?>
The above example will output:
connect...
proxy::getErrorString(array (
0 => NULL,
))
proxy::getErrorString returns ''
query...
errno...
proxy::getErrorString(array (
0 => NULL,
))
proxy::getErrorString returns 'You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near \'WILL_I_EVER_LEARN_SQL?\' at line 1'
string(168) "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WILL_I_EVER_LEARN_SQL?' at line 1"
close...
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- MysqlndUhConnection::getErrorNumber() - Returns the error code for the most recent function call
- mysqli_error() - Returns a string description of the last error
- mysql_error() - Returns the text of the error message from previous MySQL operation
MysqlndUhConnection::getFieldCount
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getFieldCount — Returns the number of columns for the most recent query
Description
$connection
) : intReturns the number of columns for the most recent query.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Number of columns.
Examples
MysqlndUhConnection::getFieldCount() is not only executed after the invocation of a user space API call which maps directly to it but also called internally.
Example #1 MysqlndUhConnection::getFieldCount() example
<?php
class proxy extends MysqlndUhConnection {
public function getFieldCount($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getFieldCount($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->query("WILL_I_EVER_LEARN_SQL?");
var_dump($mysqli->field_count);
$mysqli->query("SELECT 1, 2, 3 FROM DUAL");
var_dump($mysqli->field_count);
?>
The above example will output:
proxy::getFieldCount(array (
0 => NULL,
))
proxy::getFieldCount returns 0
int(0)
proxy::getFieldCount(array (
0 => NULL,
))
proxy::getFieldCount returns 3
proxy::getFieldCount(array (
0 => NULL,
))
proxy::getFieldCount returns 3
int(3)
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_field_count() - Returns the number of columns for the most recent query
MysqlndUhConnection::getHostInformation
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getHostInformation — Returns a string representing the type of connection used
Description
$connection
) : stringReturns a string representing the type of connection used.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Connection description.
Examples
Example #1 MysqlndUhConnection::getHostInformation() example
<?php
class proxy extends MysqlndUhConnection {
public function getHostInformation($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getHostInformation($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
var_dump($mysqli->host_info);
?>
The above example will output:
proxy::getHostInformation(array (
0 => NULL,
))
proxy::getHostInformation returns 'Localhost via UNIX socket'
string(25) "Localhost via UNIX socket"
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_get_host_info() - Returns a string representing the type of connection used
- mysql_get_host_info() - Get MySQL host info
MysqlndUhConnection::getLastInsertId
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getLastInsertId — Returns the auto generated id used in the last query
Description
$connection
) : intReturns the auto generated id used in the last query.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Last insert id.
Examples
Example #1 MysqlndUhConnection::getLastInsertId() example
<?php
class proxy extends MysqlndUhConnection {
public function getLastInsertId($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getLastInsertId($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->query("DROP TABLE IF EXISTS test");
$mysqli->query("CREATE TABLE test(id INT AUTO_INCREMENT PRIMARY KEY, col VARCHAR(255))");
$mysqli->query("INSERT INTO test(col) VALUES ('a')");
var_dump($mysqli->insert_id);
?>
The above example will output:
proxy::getLastInsertId(array (
0 => NULL,
))
proxy::getLastInsertId returns 1
int(1)
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_insert_id() - Returns the auto generated id used in the latest query
- mysql_insert_id() - Get the ID generated in the last query
MysqlndUhConnection::getLastMessage
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getLastMessage — Retrieves information about the most recently executed query
Description
$connection
) : voidRetrieves information about the most recently executed query.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Last message. Trying to return a string longer than 511 bytes
will cause an error of the type E_WARNING and
result in the string being truncated.
Examples
Example #1 MysqlndUhConnection::getLastMessage() example
<?php
class proxy extends MysqlndUhConnection {
public function getLastMessage($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getLastMessage($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
var_dump($mysqli->info);
$mysqli->query("DROP TABLE IF EXISTS test");
var_dump($mysqli->info);
?>
The above example will output:
proxy::getLastMessage(array (
0 => NULL,
))
proxy::getLastMessage returns ''
string(0) ""
proxy::getLastMessage(array (
0 => NULL,
))
proxy::getLastMessage returns ''
string(0) ""
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_info() - Retrieves information about the most recently executed query
- mysql_info() - Get information about the most recent query
MysqlndUhConnection::getProtocolInformation
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getProtocolInformation — Returns the version of the MySQL protocol used
Description
$connection
) : stringReturns the version of the MySQL protocol used.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
The protocol version.
Examples
Example #1 MysqlndUhConnection::getProtocolInformation() example
<?php
class proxy extends MysqlndUhConnection {
public function getProtocolInformation($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getProtocolInformation($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
var_dump($mysqli->protocol_version);
?>
The above example will output:
proxy::getProtocolInformation(array (
0 => NULL,
))
proxy::getProtocolInformation returns 10
int(10)
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_get_proto_info() - Returns the version of the MySQL protocol used
- mysql_get_proto_info() - Get MySQL protocol info
MysqlndUhConnection::getServerInformation
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getServerInformation — Returns the version of the MySQL server
Description
$connection
) : stringReturns the version of the MySQL server.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
The server version.
Examples
Example #1 MysqlndUhConnection::getServerInformation() example
<?php
class proxy extends MysqlndUhConnection {
public function getServerInformation($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getServerInformation($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
var_dump($mysqli->server_info);
?>
The above example will output:
proxy::getServerInformation(array (
0 => NULL,
))
proxy::getServerInformation returns '5.1.45-debug-log'
string(16) "5.1.45-debug-log"
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_get_server_info() - Returns the version of the MySQL server
- mysql_get_server_info() - Get MySQL server info
MysqlndUhConnection::getServerStatistics
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getServerStatistics — Gets the current system status
Description
$connection
) : stringGets the current system status.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
The system status message.
Examples
Example #1 MysqlndUhConnection::getServerStatistics() example
<?php
class proxy extends MysqlndUhConnection {
public function getServerStatistics($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getServerStatistics($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
var_dump(mysqli_stat($mysqli));
?>
The above example will output:
proxy::getServerStatistics(array (
0 => NULL,
))
proxy::getServerStatistics returns 'Uptime: 2059995 Threads: 1 Questions: 126157 Slow queries: 0 Opens: 6377 Flush tables: 1 Open tables: 18 Queries per second avg: 0.61'
string(140) "Uptime: 2059995 Threads: 1 Questions: 126157 Slow queries: 0 Opens: 6377 Flush tables: 1 Open tables: 18 Queries per second avg: 0.61"
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_stat() - Gets the current system status
- mysql_stat() - Get current system status
MysqlndUhConnection::getServerVersion
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getServerVersion — Returns the version of the MySQL server as an integer
Description
$connection
) : intReturns the version of the MySQL server as an integer.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
The MySQL version.
Examples
Example #1 MysqlndUhConnection::getServerVersion() example
<?php
class proxy extends MysqlndUhConnection {
public function getServerVersion($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getServerVersion($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
var_dump($mysqli->server_version);
?>
The above example will output:
proxy::getServerVersion(array (
0 => NULL,
))
proxy::getServerVersion returns 50145
int(50145)
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_get_server_version() - Returns the version of the MySQL server as an integer
- mysql_get_server_version()
MysqlndUhConnection::getSqlstate
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getSqlstate — Returns the SQLSTATE error from previous MySQL operation
Description
$connection
) : stringReturns the SQLSTATE error from previous MySQL operation.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
The SQLSTATE code.
Examples
Example #1 MysqlndUhConnection::getSqlstate() example
<?php
class proxy extends MysqlndUhConnection {
public function getSqlstate($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getSqlstate($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
var_dump($mysqli->sqlstate);
$mysqli->query("AN_INVALID_REQUEST_TO_PROVOKE_AN_ERROR");
var_dump($mysqli->sqlstate);
?>
The above example will output:
proxy::getSqlstate(array (
0 => NULL,
))
proxy::getSqlstate returns '00000'
string(5) "00000"
proxy::getSqlstate(array (
0 => NULL,
))
proxy::getSqlstate returns '42000'
string(5) "42000"
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_sql_state()
MysqlndUhConnection::getStatistics
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getStatistics — Returns statistics about the client connection
Description
$connection
) : arrayReturns statistics about the client connection.
This function is currently not documented; only its argument list is available.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Connection statistics collected by mysqlnd.
Examples
Example #1 MysqlndUhConnection::getStatistics() example
<?php
class proxy extends MysqlndUhConnection {
public function getStatistics($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getStatistics($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
var_dump($mysqli->get_connection_stats());
?>
The above example will output:
proxy::getStatistics(array (
0 => NULL,
))
proxy::getStatistics returns array (
'bytes_sent' => '73',
'bytes_received' => '77',
'packets_sent' => '2',
'packets_received' => '2',
'protocol_overhead_in' => '8',
'protocol_overhead_out' => '8',
'bytes_received_ok_packet' => '0',
'bytes_received_eof_packet' => '0',
'bytes_received_rset_header_packet' => '0',
'bytes_received_rset_field_meta_packet' => '0',
'bytes_received_rset_row_packet' => '0',
'bytes_received_prepare_response_packet' => '0',
'bytes_received_change_user_packet' => '0',
'packets_sent_command' => '0',
'packets_received_ok' => '0',
'packets_received_eof' => '0',
'packets_received_rset_header' => '0',
'packets_received_rset_field_meta' => '0',
'packets_received_rset_row' => '0',
'packets_received_prepare_response' => '0',
'packets_received_change_user' => '0',
'result_set_queries' => '0',
'non_result_set_queries' => '0',
'no_index_used' => '0',
'bad_index_used' => '0',
'slow_queries' => '0',
'buffered_sets' => '0',
'unbuffered_sets' => '0',
'ps_buffered_sets' => '0',
'ps_unbuffered_sets' => '0',
'flushed_normal_sets' => '0',
'flushed_ps_sets' => '0',
'ps_prepared_never_executed' => '0',
'ps_prepared_once_executed' => '0',
'rows_fetched_from_server_normal' => '0',
'rows_fetched_from_server_ps' => '0',
'rows_buffered_from_client_normal' => '0',
'rows_buffered_from_client_ps' => '0',
'rows_fetched_from_client_normal_buffered' => '0',
'rows_fetched_from_client_normal_unbuffered' => '0',
'rows_fetched_from_client_ps_buffered' => '0',
'rows_fetched_from_client_ps_unbuffered' => '0',
'rows_fetched_from_client_ps_cursor' => '0',
'rows_affected_normal' => '0',
'rows_affected_ps' => '0',
'rows_skipped_normal' => '0',
'rows_skipped_ps' => '0',
'copy_on_write_saved' => '0',
'copy_on_write_performed' => '0',
'command_buffer_too_small' => '0',
'connect_success' => '1',
'connect_failure' => '0',
'connection_reused' => '0',
'reconnect' => '0',
'pconnect_success' => '0',
'active_connections' => '1',
'active_persistent_connections' => '0',
'explicit_close' => '0',
'implicit_close' => '0',
'disconnect_close' => '0',
'in_middle_of_command_close' => '0',
'explicit_free_result' => '0',
'implicit_free_result' => '0',
'explicit_stmt_close' => '0',
'implicit_stmt_close' => '0',
'mem_emalloc_count' => '0',
'mem_emalloc_amount' => '0',
'mem_ecalloc_count' => '0',
'mem_ecalloc_amount' => '0',
'mem_erealloc_count' => '0',
'mem_erealloc_amount' => '0',
'mem_efree_count' => '0',
'mem_efree_amount' => '0',
'mem_malloc_count' => '0',
'mem_malloc_amount' => '0',
'mem_calloc_count' => '0',
'mem_calloc_amount' => '0',
'mem_realloc_count' => '0',
'mem_realloc_amount' => '0',
'mem_free_count' => '0',
'mem_free_amount' => '0',
'mem_estrndup_count' => '0',
'mem_strndup_count' => '0',
'mem_estndup_count' => '0',
'mem_strdup_count' => '0',
'proto_text_fetched_null' => '0',
'proto_text_fetched_bit' => '0',
'proto_text_fetched_tinyint' => '0',
'proto_text_fetched_short' => '0',
'proto_text_fetched_int24' => '0',
'proto_text_fetched_int' => '0',
'proto_text_fetched_bigint' => '0',
'proto_text_fetched_decimal' => '0',
'proto_text_fetched_float' => '0',
'proto_text_fetched_double' => '0',
'proto_text_fetched_date' => '0',
'proto_text_fetched_year' => '0',
'proto_text_fetched_time' => '0',
'proto_text_fetched_datetime' => '0',
'proto_text_fetched_timestamp' => '0',
'proto_text_fetched_string' => '0',
'proto_text_fetched_blob' => '0',
'proto_text_fetched_enum' => '0',
'proto_text_fetched_set' => '0',
'proto_text_fetched_geometry' => '0',
'proto_text_fetched_other' => '0',
'proto_binary_fetched_null' => '0',
'proto_binary_fetched_bit' => '0',
'proto_binary_fetched_tinyint' => '0',
'proto_binary_fetched_short' => '0',
'proto_binary_fetched_int24' => '0',
'proto_binary_fetched_int' => '0',
'proto_binary_fetched_bigint' => '0',
'proto_binary_fetched_decimal' => '0',
'proto_binary_fetched_float' => '0',
'proto_binary_fetched_double' => '0',
'proto_binary_fetched_date' => '0',
'proto_binary_fetched_year' => '0',
'proto_binary_fetched_time' => '0',
'proto_binary_fetched_datetime' => '0',
'proto_binary_fetched_timestamp' => '0',
'proto_binary_fetched_string' => '0',
'proto_binary_fetched_blob' => '0',
'proto_binary_fetched_enum' => '0',
'proto_binary_fetched_set' => '0',
'proto_binary_fetched_geometry' => '0',
'proto_binary_fetched_other' => '0',
'init_command_executed_count' => '0',
'init_command_failed_count' => '0',
'com_quit' => '0',
'com_init_db' => '0',
'com_query' => '0',
'com_field_list' => '0',
'com_create_db' => '0',
'com_drop_db' => '0',
'com_refresh' => '0',
'com_shutdown' => '0',
'com_statistics' => '0',
'com_process_info' => '0',
'com_connect' => '0',
'com_process_kill' => '0',
'com_debug' => '0',
'com_ping' => '0',
'com_time' => '0',
'com_delayed_insert' => '0',
'com_change_user' => '0',
'com_binlog_dump' => '0',
'com_table_dump' => '0',
'com_connect_out' => '0',
'com_register_slave' => '0',
'com_stmt_prepare' => '0',
'com_stmt_execute' => '0',
'com_stmt_send_long_data' => '0',
'com_stmt_close' => '0',
'com_stmt_reset' => '0',
'com_stmt_set_option' => '0',
'com_stmt_fetch' => '0',
'com_deamon' => '0',
'bytes_received_real_data_normal' => '0',
'bytes_received_real_data_ps' => '0',
)
array(160) {
["bytes_sent"]=>
string(2) "73"
["bytes_received"]=>
string(2) "77"
["packets_sent"]=>
string(1) "2"
["packets_received"]=>
string(1) "2"
["protocol_overhead_in"]=>
string(1) "8"
["protocol_overhead_out"]=>
string(1) "8"
["bytes_received_ok_packet"]=>
string(1) "0"
["bytes_received_eof_packet"]=>
string(1) "0"
["bytes_received_rset_header_packet"]=>
string(1) "0"
["bytes_received_rset_field_meta_packet"]=>
string(1) "0"
["bytes_received_rset_row_packet"]=>
string(1) "0"
["bytes_received_prepare_response_packet"]=>
string(1) "0"
["bytes_received_change_user_packet"]=>
string(1) "0"
["packets_sent_command"]=>
string(1) "0"
["packets_received_ok"]=>
string(1) "0"
["packets_received_eof"]=>
string(1) "0"
["packets_received_rset_header"]=>
string(1) "0"
["packets_received_rset_field_meta"]=>
string(1) "0"
["packets_received_rset_row"]=>
string(1) "0"
["packets_received_prepare_response"]=>
string(1) "0"
["packets_received_change_user"]=>
string(1) "0"
["result_set_queries"]=>
string(1) "0"
["non_result_set_queries"]=>
string(1) "0"
["no_index_used"]=>
string(1) "0"
["bad_index_used"]=>
string(1) "0"
["slow_queries"]=>
string(1) "0"
["buffered_sets"]=>
string(1) "0"
["unbuffered_sets"]=>
string(1) "0"
["ps_buffered_sets"]=>
string(1) "0"
["ps_unbuffered_sets"]=>
string(1) "0"
["flushed_normal_sets"]=>
string(1) "0"
["flushed_ps_sets"]=>
string(1) "0"
["ps_prepared_never_executed"]=>
string(1) "0"
["ps_prepared_once_executed"]=>
string(1) "0"
["rows_fetched_from_server_normal"]=>
string(1) "0"
["rows_fetched_from_server_ps"]=>
string(1) "0"
["rows_buffered_from_client_normal"]=>
string(1) "0"
["rows_buffered_from_client_ps"]=>
string(1) "0"
["rows_fetched_from_client_normal_buffered"]=>
string(1) "0"
["rows_fetched_from_client_normal_unbuffered"]=>
string(1) "0"
["rows_fetched_from_client_ps_buffered"]=>
string(1) "0"
["rows_fetched_from_client_ps_unbuffered"]=>
string(1) "0"
["rows_fetched_from_client_ps_cursor"]=>
string(1) "0"
["rows_affected_normal"]=>
string(1) "0"
["rows_affected_ps"]=>
string(1) "0"
["rows_skipped_normal"]=>
string(1) "0"
["rows_skipped_ps"]=>
string(1) "0"
["copy_on_write_saved"]=>
string(1) "0"
["copy_on_write_performed"]=>
string(1) "0"
["command_buffer_too_small"]=>
string(1) "0"
["connect_success"]=>
string(1) "1"
["connect_failure"]=>
string(1) "0"
["connection_reused"]=>
string(1) "0"
["reconnect"]=>
string(1) "0"
["pconnect_success"]=>
string(1) "0"
["active_connections"]=>
string(1) "1"
["active_persistent_connections"]=>
string(1) "0"
["explicit_close"]=>
string(1) "0"
["implicit_close"]=>
string(1) "0"
["disconnect_close"]=>
string(1) "0"
["in_middle_of_command_close"]=>
string(1) "0"
["explicit_free_result"]=>
string(1) "0"
["implicit_free_result"]=>
string(1) "0"
["explicit_stmt_close"]=>
string(1) "0"
["implicit_stmt_close"]=>
string(1) "0"
["mem_emalloc_count"]=>
string(1) "0"
["mem_emalloc_amount"]=>
string(1) "0"
["mem_ecalloc_count"]=>
string(1) "0"
["mem_ecalloc_amount"]=>
string(1) "0"
["mem_erealloc_count"]=>
string(1) "0"
["mem_erealloc_amount"]=>
string(1) "0"
["mem_efree_count"]=>
string(1) "0"
["mem_efree_amount"]=>
string(1) "0"
["mem_malloc_count"]=>
string(1) "0"
["mem_malloc_amount"]=>
string(1) "0"
["mem_calloc_count"]=>
string(1) "0"
["mem_calloc_amount"]=>
string(1) "0"
["mem_realloc_count"]=>
string(1) "0"
["mem_realloc_amount"]=>
string(1) "0"
["mem_free_count"]=>
string(1) "0"
["mem_free_amount"]=>
string(1) "0"
["mem_estrndup_count"]=>
string(1) "0"
["mem_strndup_count"]=>
string(1) "0"
["mem_estndup_count"]=>
string(1) "0"
["mem_strdup_count"]=>
string(1) "0"
["proto_text_fetched_null"]=>
string(1) "0"
["proto_text_fetched_bit"]=>
string(1) "0"
["proto_text_fetched_tinyint"]=>
string(1) "0"
["proto_text_fetched_short"]=>
string(1) "0"
["proto_text_fetched_int24"]=>
string(1) "0"
["proto_text_fetched_int"]=>
string(1) "0"
["proto_text_fetched_bigint"]=>
string(1) "0"
["proto_text_fetched_decimal"]=>
string(1) "0"
["proto_text_fetched_float"]=>
string(1) "0"
["proto_text_fetched_double"]=>
string(1) "0"
["proto_text_fetched_date"]=>
string(1) "0"
["proto_text_fetched_year"]=>
string(1) "0"
["proto_text_fetched_time"]=>
string(1) "0"
["proto_text_fetched_datetime"]=>
string(1) "0"
["proto_text_fetched_timestamp"]=>
string(1) "0"
["proto_text_fetched_string"]=>
string(1) "0"
["proto_text_fetched_blob"]=>
string(1) "0"
["proto_text_fetched_enum"]=>
string(1) "0"
["proto_text_fetched_set"]=>
string(1) "0"
["proto_text_fetched_geometry"]=>
string(1) "0"
["proto_text_fetched_other"]=>
string(1) "0"
["proto_binary_fetched_null"]=>
string(1) "0"
["proto_binary_fetched_bit"]=>
string(1) "0"
["proto_binary_fetched_tinyint"]=>
string(1) "0"
["proto_binary_fetched_short"]=>
string(1) "0"
["proto_binary_fetched_int24"]=>
string(1) "0"
["proto_binary_fetched_int"]=>
string(1) "0"
["proto_binary_fetched_bigint"]=>
string(1) "0"
["proto_binary_fetched_decimal"]=>
string(1) "0"
["proto_binary_fetched_float"]=>
string(1) "0"
["proto_binary_fetched_double"]=>
string(1) "0"
["proto_binary_fetched_date"]=>
string(1) "0"
["proto_binary_fetched_year"]=>
string(1) "0"
["proto_binary_fetched_time"]=>
string(1) "0"
["proto_binary_fetched_datetime"]=>
string(1) "0"
["proto_binary_fetched_timestamp"]=>
string(1) "0"
["proto_binary_fetched_string"]=>
string(1) "0"
["proto_binary_fetched_blob"]=>
string(1) "0"
["proto_binary_fetched_enum"]=>
string(1) "0"
["proto_binary_fetched_set"]=>
string(1) "0"
["proto_binary_fetched_geometry"]=>
string(1) "0"
["proto_binary_fetched_other"]=>
string(1) "0"
["init_command_executed_count"]=>
string(1) "0"
["init_command_failed_count"]=>
string(1) "0"
["com_quit"]=>
string(1) "0"
["com_init_db"]=>
string(1) "0"
["com_query"]=>
string(1) "0"
["com_field_list"]=>
string(1) "0"
["com_create_db"]=>
string(1) "0"
["com_drop_db"]=>
string(1) "0"
["com_refresh"]=>
string(1) "0"
["com_shutdown"]=>
string(1) "0"
["com_statistics"]=>
string(1) "0"
["com_process_info"]=>
string(1) "0"
["com_connect"]=>
string(1) "0"
["com_process_kill"]=>
string(1) "0"
["com_debug"]=>
string(1) "0"
["com_ping"]=>
string(1) "0"
["com_time"]=>
string(1) "0"
["com_delayed_insert"]=>
string(1) "0"
["com_change_user"]=>
string(1) "0"
["com_binlog_dump"]=>
string(1) "0"
["com_table_dump"]=>
string(1) "0"
["com_connect_out"]=>
string(1) "0"
["com_register_slave"]=>
string(1) "0"
["com_stmt_prepare"]=>
string(1) "0"
["com_stmt_execute"]=>
string(1) "0"
["com_stmt_send_long_data"]=>
string(1) "0"
["com_stmt_close"]=>
string(1) "0"
["com_stmt_reset"]=>
string(1) "0"
["com_stmt_set_option"]=>
string(1) "0"
["com_stmt_fetch"]=>
string(1) "0"
["com_deamon"]=>
string(1) "0"
["bytes_received_real_data_normal"]=>
string(1) "0"
["bytes_received_real_data_ps"]=>
string(1) "0"
}
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_get_connection_stats() - Returns statistics about the client connection
MysqlndUhConnection::getThreadId
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getThreadId — Returns the thread ID for the current connection
Description
$connection
) : intReturns the thread ID for the current connection.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Connection thread id.
Examples
Example #1 MysqlndUhConnection::getThreadId() example
<?php
class proxy extends MysqlndUhConnection {
public function getThreadId($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getThreadId($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
var_dump($mysqli->thread_id);
?>
The above example will output:
proxy::getThreadId(array (
0 => NULL,
))
proxy::getThreadId returns 27646
int(27646)
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_thread_id() - Returns the thread ID for the current connection
- mysql_thread_id() - Return the current thread ID
MysqlndUhConnection::getWarningCount
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::getWarningCount — Returns the number of warnings from the last query for the given link
Description
$connection
) : intReturns the number of warnings from the last query for the given link.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Number of warnings.
Examples
Example #1 MysqlndUhConnection::getWarningCount() example
<?php
class proxy extends MysqlndUhConnection {
public function getWarningCount($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::getWarningCount($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
var_dump($mysqli->warning_count);
?>
The above example will output:
proxy::getWarningCount(array (
0 => NULL,
))
proxy::getWarningCount returns 0
int(0)
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_warning_count() - Returns the number of warnings from the last query for the given link
MysqlndUhConnection::init
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::init — Initialize mysqlnd connection
Description
$connection
) : boolInitialize mysqlnd connection. This is an mysqlnd internal call to initialize the connection object.
Note:
Failing to call the parent implementation may cause memory leaks or crash PHP. This is not considered a bug. Please, keep in mind that the
mysqlndlibrary functions have never been designed to be exposed to the user space.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::init() example
<?php
class proxy extends MysqlndUhConnection {
public function init($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::init($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
?>
The above example will output:
proxy::init(array (
0 => NULL,
))
proxy::init returns true
MysqlndUhConnection::killConnection
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::killConnection — Asks the server to kill a MySQL thread
Description
$connection
, int $pid
) : boolAsks the server to kill a MySQL thread.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
pid -
Thread Id of the connection to be killed.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::kill() example
<?php
class proxy extends MysqlndUhConnection {
public function killConnection($res, $pid) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::killConnection($res, $pid);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->kill($mysqli->thread_id);
?>
The above example will output:
proxy::killConnection(array (
0 => NULL,
1 => 27650,
))
proxy::killConnection returns true
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_kill() - Asks the server to kill a MySQL thread
MysqlndUhConnection::listFields
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::listFields — List MySQL table fields
Description
$connection
, string $table
, string $achtung_wild
) : arrayList MySQL table fields.
This function is currently not documented; only its argument list is available.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
table -
The name of the table that's being queried.
-
pattern -
Name pattern.
Return Values
Examples
Example #1 MysqlndUhConnection::listFields() example
<?php
class proxy extends MysqlndUhConnection {
public function listFields($res, $table, $pattern) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::listFields($res, $table, $pattern);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysql = mysql_connect("localhost", "root", "");
mysql_select_db("test", $mysql);
mysql_query("DROP TABLE IF EXISTS test_a", $mysql);
mysql_query("CREATE TABLE test_a(id INT, col1 VARCHAR(255))", $mysql);
$res = mysql_list_fields("test", "test_a", $mysql);
printf("num_rows = %d\n", mysql_num_rows($res));
while ($row = mysql_fetch_assoc($res))
var_dump($row);
?>
The above example will output:
proxy::listFields(array (
0 => NULL,
1 => 'test_a',
2 => '',
))
proxy::listFields returns NULL
num_rows = 0
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysql_list_fields() - List MySQL table fields
MysqlndUhConnection::listMethod
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::listMethod — Wrapper for assorted list commands
Description
$connection
, string $query
, string $achtung_wild
, string $par1
) : voidWrapper for assorted list commands.
This function is currently not documented; only its argument list is available.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
query -
SHOW command to be executed.
-
achtung_wild -
-
par1 -
Return Values
Return Values
TODO
Examples
Example #1 MysqlndUhConnection::listMethod() example
<?php
class proxy extends MysqlndUhConnection {
public function listMethod($res, $query, $pattern, $par1) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::listMethod($res, $query, $pattern, $par1);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysql = mysql_connect("localhost", "root", "");
$res = mysql_list_dbs($mysql);
printf("num_rows = %d\n", mysql_num_rows($res));
while ($row = mysql_fetch_assoc($res))
var_dump($row);
?>
The above example will output:
proxy::listMethod(array (
0 => NULL,
1 => 'SHOW DATABASES',
2 => '',
3 => '',
))
proxy::listMethod returns NULL
num_rows = 6
array(1) {
["Database"]=>
string(18) "information_schema"
}
array(1) {
["Database"]=>
string(5) "mysql"
}
array(1) {
["Database"]=>
string(8) "oxid_new"
}
array(1) {
["Database"]=>
string(7) "phptest"
}
array(1) {
["Database"]=>
string(7) "pushphp"
}
array(1) {
["Database"]=>
string(4) "test"
}
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysql_list_dbs() - List databases available on a MySQL server
MysqlndUhConnection::moreResults
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::moreResults — Check if there are any more query results from a multi query
Description
$connection
) : boolCheck if there are any more query results from a multi query.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::moreResults() example
<?php
class proxy extends MysqlndUhConnection {
public function moreResults($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::moreResults($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->multi_query("SELECT 1 AS _one; SELECT 2 AS _two");
do {
$res = $mysqli->store_result();
var_dump($res->fetch_assoc());
printf("%s\n", str_repeat("-", 40));
} while ($mysqli->more_results() && $mysqli->next_result());
?>
The above example will output:
array(1) {
["_one"]=>
string(1) "1"
}
----------------------------------------
proxy::moreResults(array (
0 => NULL,
))
proxy::moreResults returns true
proxy::moreResults(array (
0 => NULL,
))
proxy::moreResults returns true
array(1) {
["_two"]=>
string(1) "2"
}
----------------------------------------
proxy::moreResults(array (
0 => NULL,
))
proxy::moreResults returns false
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_more_results() - Check if there are any more query results from a multi query
MysqlndUhConnection::nextResult
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::nextResult — Prepare next result from multi_query
Description
$connection
) : boolPrepare next result from multi_query.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::nextResult() example
<?php
class proxy extends MysqlndUhConnection {
public function nextResult($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::nextResult($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->multi_query("SELECT 1 AS _one; SELECT 2 AS _two");
do {
$res = $mysqli->store_result();
var_dump($res->fetch_assoc());
printf("%s\n", str_repeat("-", 40));
} while ($mysqli->more_results() && $mysqli->next_result());
?>
The above example will output:
array(1) {
["_one"]=>
string(1) "1"
}
----------------------------------------
proxy::nextResult(array (
0 => NULL,
))
proxy::nextResult returns true
array(1) {
["_two"]=>
string(1) "2"
}
----------------------------------------
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_next_result() - Prepare next result from multi_query
MysqlndUhConnection::ping
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::ping — Pings a server connection, or tries to reconnect if the connection has gone down
Description
$connection
) : boolPings a server connection, or tries to reconnect if the connection has gone down.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::ping() example
<?php
class proxy extends MysqlndUhConnection {
public function ping($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::ping($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->ping();
?>
The above example will output:
proxy::ping(array (
0 => NULL,
))
proxy::ping returns true
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_ping() - Pings a server connection, or tries to reconnect if the connection has gone down
- mysql_ping() - Ping a server connection or reconnect if there is no connection
MysqlndUhConnection::query
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::query — Performs a query on the database
Description
$connection
, string $query
) : boolPerforms a query on the database (COM_QUERY).
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
query -
The query string.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::query() example
<?php
class proxy extends MysqlndUhConnection {
public function query($res, $query) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$query = "SELECT 'How about query rewriting?'";
$ret = parent::query($res, $query);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$res = $mysqli->query("SELECT 'Welcome mysqlnd_uh!' FROM DUAL");
var_dump($res->fetch_assoc());
?>
The above example will output:
proxy::query(array (
0 => NULL,
1 => 'SELECT \'Welcome mysqlnd_uh!\' FROM DUAL',
))
proxy::query returns true
array(1) {
["How about query rewriting?"]=>
string(26) "How about query rewriting?"
}
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_query() - Performs a query on the database
- mysql_query() - Send a MySQL query
MysqlndUhConnection::queryReadResultsetHeader
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::queryReadResultsetHeader — Read a result set header
Description
$connection
, mysqlnd_statement $mysqlnd_stmt
) : boolRead a result set header.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
mysqlnd_stmt -
Mysqlnd statement handle. Do not modify! Set to
NULL, if function is not used in the context of a prepared statement.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::queryReadResultsetHeader() example
<?php
class proxy extends MysqlndUhConnection {
public function queryReadResultsetHeader($res, $stmt) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::queryReadResultsetHeader($res, $stmt);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$res = $mysqli->query("SELECT 'Welcome mysqlnd_uh!' FROM DUAL");
var_dump($res->fetch_assoc());
?>
The above example will output:
proxy::queryReadResultsetHeader(array (
0 => NULL,
1 => NULL,
))
proxy::queryReadResultsetHeader returns true
array(1) {
["Welcome mysqlnd_uh!"]=>
string(19) "Welcome mysqlnd_uh!"
}
MysqlndUhConnection::reapQuery
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::reapQuery — Get result from async query
Description
$connection
) : boolGet result from async query.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::reapQuery() example
<?php
class proxy extends MysqlndUhConnection {
public function reapQuery($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::reapQuery($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$conn1 = new mysqli("localhost", "root", "", "test");
$conn2 = new mysqli("localhost", "root", "", "test");
$conn1->query("SELECT 1 as 'one', SLEEP(1) AS _sleep FROM DUAL", MYSQLI_ASYNC | MYSQLI_USE_RESULT);
$conn2->query("SELECT 1.1 as 'one dot one' FROM DUAL", MYSQLI_ASYNC | MYSQLI_USE_RESULT);
$links = array(
$conn1->thread_id => array('link' => $conn1, 'processed' => false),
$conn2->thread_id => array('link' => $conn2, 'processed' => false)
);
$saved_errors = array();
do {
$poll_links = $poll_errors = $poll_reject = array();
foreach ($links as $thread_id => $link) {
if (!$link['processed']) {
$poll_links[] = $link['link'];
$poll_errors[] = $link['link'];
$poll_reject[] = $link['link'];
}
}
if (0 == count($poll_links))
break;
if (0 == ($num_ready = mysqli_poll($poll_links, $poll_errors, $poll_reject, 0, 200000)))
continue;
if (!empty($poll_errors)) {
die(var_dump($poll_errors));
}
foreach ($poll_links as $link) {
$thread_id = mysqli_thread_id($link);
$links[$thread_id]['processed'] = true;
if (is_object($res = mysqli_reap_async_query($link))) {
// result set object
while ($row = mysqli_fetch_assoc($res)) {
// eat up all results
var_dump($row);
}
mysqli_free_result($res);
} else {
// either there is no result (no SELECT) or there is an error
if (mysqli_errno($link) > 0) {
$saved_errors[$thread_id] = mysqli_errno($link);
printf("'%s' caused %d\n", $links[$thread_id]['query'], mysqli_errno($link));
}
}
}
} while (true);
?>
The above example will output:
proxy::reapQuery(array (
0 => NULL,
))
proxy::reapQuery returns true
array(1) {
["one dot one"]=>
string(3) "1.1"
}
proxy::reapQuery(array (
0 => NULL,
))
proxy::reapQuery returns true
array(2) {
["one"]=>
string(1) "1"
["_sleep"]=>
string(1) "0"
}
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_real_async_query()
MysqlndUhConnection::refreshServer
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::refreshServer — Flush or reset tables and caches
Description
$connection
, int $options
) : boolFlush or reset tables and caches.
This function is currently not documented; only its argument list is available.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
options -
What to refresh.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::refreshServer() example
<?php
class proxy extends MysqlndUhConnection {
public function refreshServer($res, $option) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::refreshServer($res, $option);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
mysqli_refresh($mysqli, 1);
?>
The above example will output:
proxy::refreshServer(array (
0 => NULL,
1 => 1,
))
proxy::refreshServer returns false
MysqlndUhConnection::restartPSession
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::restartPSession — Restart a persistent mysqlnd connection
Description
$connection
) : boolRestart a persistent mysqlnd connection.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::restartPSession() example
<?php
class proxy extends MysqlndUhConnection {
public function ping($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::ping($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->ping();
?>
The above example will output:
proxy::restartPSession(array (
0 => NULL,
))
proxy::restartPSession returns true
MysqlndUhConnection::selectDb
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::selectDb — Selects the default database for database queries
Description
$connection
, string $database
) : boolSelects the default database for database queries.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
database -
The database name.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::selectDb() example
<?php
class proxy extends MysqlndUhConnection {
public function selectDb($res, $database) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::selectDb($res, $database);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->select_db("mysql");
?>
The above example will output:
proxy::selectDb(array (
0 => NULL,
1 => 'mysql',
))
proxy::selectDb returns true
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_select_db() - Selects the default database for database queries
- mysql_select_db() - Select a MySQL database
MysqlndUhConnection::sendClose
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::sendClose — Sends a close command to MySQL
Description
$connection
) : boolSends a close command to MySQL.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::sendClose() example
<?php
class proxy extends MysqlndUhConnection {
public function sendClose($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::sendClose($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->close();
?>
The above example will output:
proxy::sendClose(array (
0 => NULL,
))
proxy::sendClose returns true
proxy::sendClose(array (
0 => NULL,
))
proxy::sendClose returns true
MysqlndUhConnection::sendQuery
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::sendQuery — Sends a query to MySQL
Description
$connection
, string $query
) : boolSends a query to MySQL.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
query -
The query string.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::sendQuery() example
<?php
class proxy extends MysqlndUhConnection {
public function sendQuery($res, $query) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::sendQuery($res, $query);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->query("SELECT 1");
?>
The above example will output:
proxy::sendQuery(array (
0 => NULL,
1 => 'SELECT 1',
))
proxy::sendQuery returns true
MysqlndUhConnection::serverDumpDebugInformation
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::serverDumpDebugInformation — Dump debugging information into the log for the MySQL server
Description
$connection
) : boolDump debugging information into the log for the MySQL server.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::serverDumpDebugInformation() example
<?php
class proxy extends MysqlndUhConnection {
public function serverDumpDebugInformation($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::serverDumpDebugInformation($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->dump_debug_info();
?>
The above example will output:
proxy::serverDumpDebugInformation(array (
0 => NULL,
))
proxy::serverDumpDebugInformation returns true
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_dump_debug_info() - Dump debugging information into the log
MysqlndUhConnection::setAutocommit
(PECL mysqlnd-uh >= 1.0.1-alpha)
MysqlndUhConnection::setAutocommit — Turns on or off auto-committing database modifications
Description
$connection
, int $mode
) : boolTurns on or off auto-committing database modifications
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
mode -
Whether to turn on auto-commit or not.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::setAutocommit() example
<?php
class proxy extends MysqlndUhConnection {
public function setAutocommit($res, $mode) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::setAutocommit($res, $mode);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->autocommit(false);
$mysqli->autocommit(true);
?>
The above example will output:
proxy::setAutocommit(array (
0 => NULL,
1 => 0,
))
proxy::setAutocommit returns true
proxy::setAutocommit(array (
0 => NULL,
1 => 1,
))
proxy::setAutocommit returns true
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_autocommit() - Turns on or off auto-committing database modifications
MysqlndUhConnection::setCharset
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::setCharset — Sets the default client character set
Description
$connection
, string $charset
) : boolSets the default client character set.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
charset -
The charset to be set as default.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::setCharset() example
<?php
class proxy extends MysqlndUhConnection {
public function setCharset($res, $charset) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::setCharset($res, $charset);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->set_charset("latin1");
?>
The above example will output:
proxy::setCharset(array (
0 => NULL,
1 => 'latin1',
))
proxy::setCharset returns true
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_set_charset() - Sets the default client character set
MysqlndUhConnection::setClientOption
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::setClientOption — Sets a client option
Description
$connection
, int $option
, int $value
) : boolSets a client option.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
option -
The option to be set.
-
value -
Optional option value, if required.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::setClientOption() example
<?php
function client_option_to_string($option) {
static $mapping = array(
MYSQLND_UH_MYSQLND_OPTION_OPT_CONNECT_TIMEOUT => "MYSQLND_UH_MYSQLND_OPTION_OPT_CONNECT_TIMEOUT",
MYSQLND_UH_MYSQLND_OPTION_OPT_COMPRESS => "MYSQLND_UH_MYSQLND_OPTION_OPT_COMPRESS",
MYSQLND_UH_MYSQLND_OPTION_OPT_NAMED_PIPE => "MYSQLND_UH_MYSQLND_OPTION_OPT_NAMED_PIPE",
MYSQLND_UH_MYSQLND_OPTION_INIT_COMMAND => "MYSQLND_UH_MYSQLND_OPTION_INIT_COMMAND",
MYSQLND_UH_MYSQLND_READ_DEFAULT_FILE => "MYSQLND_UH_MYSQLND_READ_DEFAULT_FILE",
MYSQLND_UH_MYSQLND_READ_DEFAULT_GROUP => "MYSQLND_UH_MYSQLND_READ_DEFAULT_GROUP",
MYSQLND_UH_MYSQLND_SET_CHARSET_DIR => "MYSQLND_UH_MYSQLND_SET_CHARSET_DIR",
MYSQLND_UH_MYSQLND_SET_CHARSET_NAME => "MYSQLND_UH_MYSQLND_SET_CHARSET_NAME",
MYSQLND_UH_MYSQLND_OPT_LOCAL_INFILE => "MYSQLND_UH_MYSQLND_OPT_LOCAL_INFILE",
MYSQLND_UH_MYSQLND_OPT_PROTOCOL => "MYSQLND_UH_MYSQLND_OPT_PROTOCOL",
MYSQLND_UH_MYSQLND_SHARED_MEMORY_BASE_NAME => "MYSQLND_UH_MYSQLND_SHARED_MEMORY_BASE_NAME",
MYSQLND_UH_MYSQLND_OPT_READ_TIMEOUT => "MYSQLND_UH_MYSQLND_OPT_READ_TIMEOUT",
MYSQLND_UH_MYSQLND_OPT_WRITE_TIMEOUT => "MYSQLND_UH_MYSQLND_OPT_WRITE_TIMEOUT",
MYSQLND_UH_MYSQLND_OPT_USE_RESULT => "MYSQLND_UH_MYSQLND_OPT_USE_RESULT",
MYSQLND_UH_MYSQLND_OPT_USE_REMOTE_CONNECTION => "MYSQLND_UH_MYSQLND_OPT_USE_REMOTE_CONNECTION",
MYSQLND_UH_MYSQLND_OPT_USE_EMBEDDED_CONNECTION => "MYSQLND_UH_MYSQLND_OPT_USE_EMBEDDED_CONNECTION",
MYSQLND_UH_MYSQLND_OPT_GUESS_CONNECTION => "MYSQLND_UH_MYSQLND_OPT_GUESS_CONNECTION",
MYSQLND_UH_MYSQLND_SET_CLIENT_IP => "MYSQLND_UH_MYSQLND_SET_CLIENT_IP",
MYSQLND_UH_MYSQLND_SECURE_AUTH => "MYSQLND_UH_MYSQLND_SECURE_AUTH",
MYSQLND_UH_MYSQLND_REPORT_DATA_TRUNCATION => "MYSQLND_UH_MYSQLND_REPORT_DATA_TRUNCATION",
MYSQLND_UH_MYSQLND_OPT_RECONNECT => "MYSQLND_UH_MYSQLND_OPT_RECONNECT",
MYSQLND_UH_MYSQLND_OPT_SSL_VERIFY_SERVER_CERT => "MYSQLND_UH_MYSQLND_OPT_SSL_VERIFY_SERVER_CERT",
MYSQLND_UH_MYSQLND_OPT_NET_CMD_BUFFER_SIZE => "MYSQLND_UH_MYSQLND_OPT_NET_CMD_BUFFER_SIZE",
MYSQLND_UH_MYSQLND_OPT_NET_READ_BUFFER_SIZE => "MYSQLND_UH_MYSQLND_OPT_NET_READ_BUFFER_SIZE",
MYSQLND_UH_MYSQLND_OPT_SSL_KEY => "MYSQLND_UH_MYSQLND_OPT_SSL_KEY",
MYSQLND_UH_MYSQLND_OPT_SSL_CERT => "MYSQLND_UH_MYSQLND_OPT_SSL_CERT",
MYSQLND_UH_MYSQLND_OPT_SSL_CA => "MYSQLND_UH_MYSQLND_OPT_SSL_CA",
MYSQLND_UH_MYSQLND_OPT_SSL_CAPATH => "MYSQLND_UH_MYSQLND_OPT_SSL_CAPATH",
MYSQLND_UH_MYSQLND_OPT_SSL_CIPHER => "MYSQLND_UH_MYSQLND_OPT_SSL_CIPHER",
MYSQLND_UH_MYSQLND_OPT_SSL_PASSPHRASE => "MYSQLND_UH_MYSQLND_OPT_SSL_PASSPHRASE",
MYSQLND_UH_SERVER_OPTION_PLUGIN_DIR => "MYSQLND_UH_SERVER_OPTION_PLUGIN_DIR",
MYSQLND_UH_SERVER_OPTION_DEFAULT_AUTH => "MYSQLND_UH_SERVER_OPTION_DEFAULT_AUTH",
MYSQLND_UH_SERVER_OPTION_SET_CLIENT_IP => "MYSQLND_UH_SERVER_OPTION_SET_CLIENT_IP"
);
if (version_compare(PHP_VERSION, '5.3.99-dev', '>')) {
$mapping[MYSQLND_UH_MYSQLND_OPT_MAX_ALLOWED_PACKET] = "MYSQLND_UH_MYSQLND_OPT_MAX_ALLOWED_PACKET";
$mapping[MYSQLND_UH_MYSQLND_OPT_AUTH_PROTOCOL] = "MYSQLND_UH_MYSQLND_OPT_AUTH_PROTOCOL";
}
if (defined("MYSQLND_UH_MYSQLND_OPT_INT_AND_FLOAT_NATIVE")) {
/* special mysqlnd build */
$mapping["MYSQLND_UH_MYSQLND_OPT_INT_AND_FLOAT_NATIVE"] = "MYSQLND_UH_MYSQLND_OPT_INT_AND_FLOAT_NATIVE";
}
return (isset($mapping[$option])) ? $mapping[$option] : 'unknown';
}
class proxy extends MysqlndUhConnection {
public function setClientOption($res, $option, $value) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
printf("Option '%s' set to %s\n", client_option_to_string($option), var_export($value, true));
$ret = parent::setClientOption($res, $option, $value);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
?>
The above example will output:
proxy::setClientOption(array (
0 => NULL,
1 => 210,
2 => 3221225472,
))
Option 'MYSQLND_UH_MYSQLND_OPT_MAX_ALLOWED_PACKET' set to 3221225472
proxy::setClientOption returns true
proxy::setClientOption(array (
0 => NULL,
1 => 211,
2 => 'mysql_native_password',
))
Option 'MYSQLND_UH_MYSQLND_OPT_AUTH_PROTOCOL' set to 'mysql_native_password'
proxy::setClientOption returns true
proxy::setClientOption(array (
0 => NULL,
1 => 8,
2 => 1,
))
Option 'MYSQLND_UH_MYSQLND_OPT_LOCAL_INFILE' set to 1
proxy::setClientOption returns true
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_real_connect() - Opens a connection to a mysql server
- mysqli_options() - Set options
MysqlndUhConnection::setServerOption
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::setServerOption — Sets a server option
Description
$connection
, int $option
) : voidSets a server option.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
option -
The option to be set.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::setServerOption() example
<?php
function server_option_to_string($option) {
$ret = 'unknown';
switch ($option) {
case MYSQLND_UH_SERVER_OPTION_MULTI_STATEMENTS_ON:
$ret = 'MYSQLND_UH_SERVER_OPTION_MULTI_STATEMENTS_ON';
break;
case MYSQLND_UH_SERVER_OPTION_MULTI_STATEMENTS_OFF:
$ret = 'MYSQLND_UH_SERVER_OPTION_MULTI_STATEMENTS_ON';
break;
}
return $ret;
}
class proxy extends MysqlndUhConnection {
public function setServerOption($res, $option) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
printf("Option '%s' set\n", server_option_to_string($option));
$ret = parent::setServerOption($res, $option);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->multi_query("SELECT 1; SELECT 2");
?>
The above example will output:
proxy::setServerOption(array (
0 => NULL,
1 => 0,
))
Option 'MYSQLND_UH_SERVER_OPTION_MULTI_STATEMENTS_ON' set
proxy::setServerOption returns true
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_real_connect() - Opens a connection to a mysql server
- mysqli_options() - Set options
- mysqli_multi_query() - Performs a query on the database
MysqlndUhConnection::shutdownServer
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::shutdownServer — The shutdownServer purpose
Description
$MYSQLND_UH_RES_MYSQLND_NAME
, string $level
) : void
This function is currently not documented; only its argument list is available.
Parameters
-
MYSQLND_UH_RES_MYSQLND_NAME -
-
level -
Return Values
MysqlndUhConnection::simpleCommand
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::simpleCommand — Sends a basic COM_* command
Description
$connection
, int $command
, string $arg
, int $ok_packet
, bool $silent
, bool $ignore_upsert_status
) : boolSends a basic COM_* command to MySQL.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
command -
The COM command to be send.
-
arg -
Optional COM command arguments.
-
ok_packet -
The OK packet type.
-
silent -
Whether mysqlnd may emit errors.
-
ignore_upsert_status -
Whether to ignore
UPDATE/INSERTstatus.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::simpleCommand() example
<?php
function server_cmd_2_string($command) {
$mapping = array(
MYSQLND_UH_MYSQLND_COM_SLEEP => "MYSQLND_UH_MYSQLND_COM_SLEEP",
MYSQLND_UH_MYSQLND_COM_QUIT => "MYSQLND_UH_MYSQLND_COM_QUIT",
MYSQLND_UH_MYSQLND_COM_INIT_DB => "MYSQLND_UH_MYSQLND_COM_INIT_DB",
MYSQLND_UH_MYSQLND_COM_QUERY => "MYSQLND_UH_MYSQLND_COM_QUERY",
MYSQLND_UH_MYSQLND_COM_FIELD_LIST => "MYSQLND_UH_MYSQLND_COM_FIELD_LIST",
MYSQLND_UH_MYSQLND_COM_CREATE_DB => "MYSQLND_UH_MYSQLND_COM_CREATE_DB",
MYSQLND_UH_MYSQLND_COM_DROP_DB => "MYSQLND_UH_MYSQLND_COM_DROP_DB",
MYSQLND_UH_MYSQLND_COM_REFRESH => "MYSQLND_UH_MYSQLND_COM_REFRESH",
MYSQLND_UH_MYSQLND_COM_SHUTDOWN => "MYSQLND_UH_MYSQLND_COM_SHUTDOWN",
MYSQLND_UH_MYSQLND_COM_STATISTICS => "MYSQLND_UH_MYSQLND_COM_STATISTICS",
MYSQLND_UH_MYSQLND_COM_PROCESS_INFO => "MYSQLND_UH_MYSQLND_COM_PROCESS_INFO",
MYSQLND_UH_MYSQLND_COM_CONNECT => "MYSQLND_UH_MYSQLND_COM_CONNECT",
MYSQLND_UH_MYSQLND_COM_PROCESS_KILL => "MYSQLND_UH_MYSQLND_COM_PROCESS_KILL",
MYSQLND_UH_MYSQLND_COM_DEBUG => "MYSQLND_UH_MYSQLND_COM_DEBUG",
MYSQLND_UH_MYSQLND_COM_PING => "MYSQLND_UH_MYSQLND_COM_PING",
MYSQLND_UH_MYSQLND_COM_TIME => "MYSQLND_UH_MYSQLND_COM_TIME",
MYSQLND_UH_MYSQLND_COM_DELAYED_INSERT => "MYSQLND_UH_MYSQLND_COM_DELAYED_INSERT",
MYSQLND_UH_MYSQLND_COM_CHANGE_USER => "MYSQLND_UH_MYSQLND_COM_CHANGE_USER",
MYSQLND_UH_MYSQLND_COM_BINLOG_DUMP => "MYSQLND_UH_MYSQLND_COM_BINLOG_DUMP",
MYSQLND_UH_MYSQLND_COM_TABLE_DUMP => "MYSQLND_UH_MYSQLND_COM_TABLE_DUMP",
MYSQLND_UH_MYSQLND_COM_CONNECT_OUT => "MYSQLND_UH_MYSQLND_COM_CONNECT_OUT",
MYSQLND_UH_MYSQLND_COM_REGISTER_SLAVED => "MYSQLND_UH_MYSQLND_COM_REGISTER_SLAVED",
MYSQLND_UH_MYSQLND_COM_STMT_PREPARE => "MYSQLND_UH_MYSQLND_COM_STMT_PREPARE",
MYSQLND_UH_MYSQLND_COM_STMT_EXECUTE => "MYSQLND_UH_MYSQLND_COM_STMT_EXECUTE",
MYSQLND_UH_MYSQLND_COM_STMT_SEND_LONG_DATA => "MYSQLND_UH_MYSQLND_COM_STMT_SEND_LONG_DATA",
MYSQLND_UH_MYSQLND_COM_STMT_CLOSE => "MYSQLND_UH_MYSQLND_COM_STMT_CLOSE",
MYSQLND_UH_MYSQLND_COM_STMT_RESET => "MYSQLND_UH_MYSQLND_COM_STMT_RESET",
MYSQLND_UH_MYSQLND_COM_SET_OPTION => "MYSQLND_UH_MYSQLND_COM_SET_OPTION",
MYSQLND_UH_MYSQLND_COM_STMT_FETCH => "MYSQLND_UH_MYSQLND_COM_STMT_FETCH",
MYSQLND_UH_MYSQLND_COM_DAEMON => "MYSQLND_UH_MYSQLND_COM_DAEMON",
MYSQLND_UH_MYSQLND_COM_END => "MYSQLND_UH_MYSQLND_COM_END",
);
return (isset($mapping[$command])) ? $mapping[$command] : 'unknown';
}
function ok_packet_2_string($ok_packet) {
$mapping = array(
MYSQLND_UH_MYSQLND_PROT_GREET_PACKET => "MYSQLND_UH_MYSQLND_PROT_GREET_PACKET",
MYSQLND_UH_MYSQLND_PROT_AUTH_PACKET => "MYSQLND_UH_MYSQLND_PROT_AUTH_PACKET",
MYSQLND_UH_MYSQLND_PROT_OK_PACKET => "MYSQLND_UH_MYSQLND_PROT_OK_PACKET",
MYSQLND_UH_MYSQLND_PROT_EOF_PACKET => "MYSQLND_UH_MYSQLND_PROT_EOF_PACKET",
MYSQLND_UH_MYSQLND_PROT_CMD_PACKET => "MYSQLND_UH_MYSQLND_PROT_CMD_PACKET",
MYSQLND_UH_MYSQLND_PROT_RSET_HEADER_PACKET => "MYSQLND_UH_MYSQLND_PROT_RSET_HEADER_PACKET",
MYSQLND_UH_MYSQLND_PROT_RSET_FLD_PACKET => "MYSQLND_UH_MYSQLND_PROT_RSET_FLD_PACKET",
MYSQLND_UH_MYSQLND_PROT_ROW_PACKET => "MYSQLND_UH_MYSQLND_PROT_ROW_PACKET",
MYSQLND_UH_MYSQLND_PROT_STATS_PACKET => "MYSQLND_UH_MYSQLND_PROT_STATS_PACKET",
MYSQLND_UH_MYSQLND_PREPARE_RESP_PACKET => "MYSQLND_UH_MYSQLND_PREPARE_RESP_PACKET",
MYSQLND_UH_MYSQLND_CHG_USER_RESP_PACKET => "MYSQLND_UH_MYSQLND_CHG_USER_RESP_PACKET",
MYSQLND_UH_MYSQLND_PROT_LAST => "MYSQLND_UH_MYSQLND_PROT_LAST",
);
return (isset($mapping[$ok_packet])) ? $mapping[$ok_packet] : 'unknown';
}
class proxy extends MysqlndUhConnection {
public function simpleCommand($conn, $command, $arg, $ok_packet, $silent, $ignore_upsert_status) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
printf("Command '%s'\n", server_cmd_2_string($command));
printf("OK packet '%s'\n", ok_packet_2_string($ok_packet));
$ret = parent::simpleCommand($conn, $command, $arg, $ok_packet, $silent, $ignore_upsert_status);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->query("SELECT 1");
?>
The above example will output:
proxy::simpleCommand(array (
0 => NULL,
1 => 3,
2 => 'SELECT 1',
3 => 13,
4 => false,
5 => false,
))
Command 'MYSQLND_UH_MYSQLND_COM_QUERY'
OK packet 'MYSQLND_UH_MYSQLND_PROT_LAST'
proxy::simpleCommand returns true
:)proxy::simpleCommand(array (
0 => NULL,
1 => 1,
2 => '',
3 => 13,
4 => true,
5 => true,
))
Command 'MYSQLND_UH_MYSQLND_COM_QUIT'
OK packet 'MYSQLND_UH_MYSQLND_PROT_LAST'
proxy::simpleCommand returns true
MysqlndUhConnection::simpleCommandHandleResponse
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::simpleCommandHandleResponse — Process a response for a basic COM_* command send to the client
Description
$connection
, int $ok_packet
, bool $silent
, int $command
, bool $ignore_upsert_status
) : boolProcess a response for a basic COM_* command send to the client.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
ok_packet -
The OK packet type.
-
silent -
Whether mysqlnd may emit errors.
-
command -
The COM command to process results from.
-
ignore_upsert_status -
Whether to ignore
UPDATE/INSERTstatus.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::simpleCommandHandleResponse() example
<?php
function server_cmd_2_string($command) {
$mapping = array(
MYSQLND_UH_MYSQLND_COM_SLEEP => "MYSQLND_UH_MYSQLND_COM_SLEEP",
MYSQLND_UH_MYSQLND_COM_QUIT => "MYSQLND_UH_MYSQLND_COM_QUIT",
MYSQLND_UH_MYSQLND_COM_INIT_DB => "MYSQLND_UH_MYSQLND_COM_INIT_DB",
MYSQLND_UH_MYSQLND_COM_QUERY => "MYSQLND_UH_MYSQLND_COM_QUERY",
MYSQLND_UH_MYSQLND_COM_FIELD_LIST => "MYSQLND_UH_MYSQLND_COM_FIELD_LIST",
MYSQLND_UH_MYSQLND_COM_CREATE_DB => "MYSQLND_UH_MYSQLND_COM_CREATE_DB",
MYSQLND_UH_MYSQLND_COM_DROP_DB => "MYSQLND_UH_MYSQLND_COM_DROP_DB",
MYSQLND_UH_MYSQLND_COM_REFRESH => "MYSQLND_UH_MYSQLND_COM_REFRESH",
MYSQLND_UH_MYSQLND_COM_SHUTDOWN => "MYSQLND_UH_MYSQLND_COM_SHUTDOWN",
MYSQLND_UH_MYSQLND_COM_STATISTICS => "MYSQLND_UH_MYSQLND_COM_STATISTICS",
MYSQLND_UH_MYSQLND_COM_PROCESS_INFO => "MYSQLND_UH_MYSQLND_COM_PROCESS_INFO",
MYSQLND_UH_MYSQLND_COM_CONNECT => "MYSQLND_UH_MYSQLND_COM_CONNECT",
MYSQLND_UH_MYSQLND_COM_PROCESS_KILL => "MYSQLND_UH_MYSQLND_COM_PROCESS_KILL",
MYSQLND_UH_MYSQLND_COM_DEBUG => "MYSQLND_UH_MYSQLND_COM_DEBUG",
MYSQLND_UH_MYSQLND_COM_PING => "MYSQLND_UH_MYSQLND_COM_PING",
MYSQLND_UH_MYSQLND_COM_TIME => "MYSQLND_UH_MYSQLND_COM_TIME",
MYSQLND_UH_MYSQLND_COM_DELAYED_INSERT => "MYSQLND_UH_MYSQLND_COM_DELAYED_INSERT",
MYSQLND_UH_MYSQLND_COM_CHANGE_USER => "MYSQLND_UH_MYSQLND_COM_CHANGE_USER",
MYSQLND_UH_MYSQLND_COM_BINLOG_DUMP => "MYSQLND_UH_MYSQLND_COM_BINLOG_DUMP",
MYSQLND_UH_MYSQLND_COM_TABLE_DUMP => "MYSQLND_UH_MYSQLND_COM_TABLE_DUMP",
MYSQLND_UH_MYSQLND_COM_CONNECT_OUT => "MYSQLND_UH_MYSQLND_COM_CONNECT_OUT",
MYSQLND_UH_MYSQLND_COM_REGISTER_SLAVED => "MYSQLND_UH_MYSQLND_COM_REGISTER_SLAVED",
MYSQLND_UH_MYSQLND_COM_STMT_PREPARE => "MYSQLND_UH_MYSQLND_COM_STMT_PREPARE",
MYSQLND_UH_MYSQLND_COM_STMT_EXECUTE => "MYSQLND_UH_MYSQLND_COM_STMT_EXECUTE",
MYSQLND_UH_MYSQLND_COM_STMT_SEND_LONG_DATA => "MYSQLND_UH_MYSQLND_COM_STMT_SEND_LONG_DATA",
MYSQLND_UH_MYSQLND_COM_STMT_CLOSE => "MYSQLND_UH_MYSQLND_COM_STMT_CLOSE",
MYSQLND_UH_MYSQLND_COM_STMT_RESET => "MYSQLND_UH_MYSQLND_COM_STMT_RESET",
MYSQLND_UH_MYSQLND_COM_SET_OPTION => "MYSQLND_UH_MYSQLND_COM_SET_OPTION",
MYSQLND_UH_MYSQLND_COM_STMT_FETCH => "MYSQLND_UH_MYSQLND_COM_STMT_FETCH",
MYSQLND_UH_MYSQLND_COM_DAEMON => "MYSQLND_UH_MYSQLND_COM_DAEMON",
MYSQLND_UH_MYSQLND_COM_END => "MYSQLND_UH_MYSQLND_COM_END",
);
return (isset($mapping[$command])) ? $mapping[$command] : 'unknown';
}
function ok_packet_2_string($ok_packet) {
$mapping = array(
MYSQLND_UH_MYSQLND_PROT_GREET_PACKET => "MYSQLND_UH_MYSQLND_PROT_GREET_PACKET",
MYSQLND_UH_MYSQLND_PROT_AUTH_PACKET => "MYSQLND_UH_MYSQLND_PROT_AUTH_PACKET",
MYSQLND_UH_MYSQLND_PROT_OK_PACKET => "MYSQLND_UH_MYSQLND_PROT_OK_PACKET",
MYSQLND_UH_MYSQLND_PROT_EOF_PACKET => "MYSQLND_UH_MYSQLND_PROT_EOF_PACKET",
MYSQLND_UH_MYSQLND_PROT_CMD_PACKET => "MYSQLND_UH_MYSQLND_PROT_CMD_PACKET",
MYSQLND_UH_MYSQLND_PROT_RSET_HEADER_PACKET => "MYSQLND_UH_MYSQLND_PROT_RSET_HEADER_PACKET",
MYSQLND_UH_MYSQLND_PROT_RSET_FLD_PACKET => "MYSQLND_UH_MYSQLND_PROT_RSET_FLD_PACKET",
MYSQLND_UH_MYSQLND_PROT_ROW_PACKET => "MYSQLND_UH_MYSQLND_PROT_ROW_PACKET",
MYSQLND_UH_MYSQLND_PROT_STATS_PACKET => "MYSQLND_UH_MYSQLND_PROT_STATS_PACKET",
MYSQLND_UH_MYSQLND_PREPARE_RESP_PACKET => "MYSQLND_UH_MYSQLND_PREPARE_RESP_PACKET",
MYSQLND_UH_MYSQLND_CHG_USER_RESP_PACKET => "MYSQLND_UH_MYSQLND_CHG_USER_RESP_PACKET",
MYSQLND_UH_MYSQLND_PROT_LAST => "MYSQLND_UH_MYSQLND_PROT_LAST",
);
return (isset($mapping[$ok_packet])) ? $mapping[$ok_packet] : 'unknown';
}
class proxy extends MysqlndUhConnection {
public function simpleCommandHandleResponse($conn, $ok_packet, $silent, $command, $ignore_upsert_status) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
printf("Command '%s'\n", server_cmd_2_string($command));
printf("OK packet '%s'\n", ok_packet_2_string($ok_packet));
$ret = parent::simpleCommandHandleResponse($conn, $ok_packet, $silent, $command, $ignore_upsert_status);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysql = mysql_connect("localhost", "root", "");
mysql_query("SELECT 1 FROM DUAL", $mysql);
?>
The above example will output:
proxy::simpleCommandHandleResponse(array (
0 => NULL,
1 => 5,
2 => false,
3 => 27,
4 => true,
))
Command 'MYSQLND_UH_MYSQLND_COM_SET_OPTION'
OK packet 'MYSQLND_UH_MYSQLND_PROT_EOF_PACKET'
proxy::simpleCommandHandleResponse returns true
MysqlndUhConnection::sslSet
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::sslSet — Used for establishing secure connections using SSL
Description
$connection
, string $key
, string $cert
, string $ca
, string $capath
, string $cipher
) : boolUsed for establishing secure connections using SSL.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
-
key -
The path name to the key file.
-
cert -
The path name to the certificate file.
-
ca -
The path name to the certificate authority file.
-
capath -
The pathname to a directory that contains trusted SSL CA certificates in PEM format.
-
cipher -
A list of allowable ciphers to use for SSL encryption.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::sslSet() example
<?php
class proxy extends MysqlndUhConnection {
public function sslSet($conn, $key, $cert, $ca, $capath, $cipher) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::sslSet($conn, $key, $cert, $ca, $capath, $cipher);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->ssl_set("key", "cert", "ca", "capath", "cipher");
?>
The above example will output:
proxy::sslSet(array (
0 => NULL,
1 => 'key',
2 => 'cert',
3 => 'ca',
4 => 'capath',
5 => 'cipher',
))
proxy::sslSet returns true
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_ssl_set() - Used for establishing secure connections using SSL
MysqlndUhConnection::stmtInit
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::stmtInit — Initializes a statement and returns a resource for use with mysqli_statement::prepare
Description
$connection
) : resourceInitializes a statement and returns a resource for use with mysqli_statement::prepare.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Resource of type Mysqlnd Prepared Statement (internal only - you must not modify it!).
The documentation may also refer to such resources using the alias name
mysqlnd_prepared_statement.
Examples
Example #1 MysqlndUhConnection::stmtInit() example
<?php
class proxy extends MysqlndUhConnection {
public function stmtInit($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
var_dump($res);
$ret = parent::stmtInit($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
var_dump($ret);
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$stmt = $mysqli->prepare("SELECT 1 AS _one FROM DUAL");
$stmt->execute();
$one = NULL;
$stmt->bind_result($one);
$stmt->fetch();
var_dump($one);
?>
The above example will output:
proxy::stmtInit(array (
0 => NULL,
))
resource(19) of type (Mysqlnd Connection)
proxy::stmtInit returns NULL
resource(246) of type (Mysqlnd Prepared Statement (internal only - you must not modify it!))
int(1)
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_stmt_init() - Initializes a statement and returns an object for use with mysqli_stmt_prepare
MysqlndUhConnection::storeResult
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::storeResult — Transfers a result set from the last query
Description
$connection
) : resourceTransfers a result set from the last query.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Resource of type Mysqlnd Resultset (internal only - you must not modify it!).
The documentation may also refer to such resources using the alias name
mysqlnd_resultset.
Examples
Example #1 MysqlndUhConnection::storeResult() example
<?php
class proxy extends MysqlndUhConnection {
public function storeResult($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::storeResult($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
var_dump($ret);
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$res = $mysqli->query("SELECT 'Also called buffered result' AS _msg FROM DUAL");
var_dump($res->fetch_assoc());
$mysqli->real_query("SELECT 'Good morning!' AS _msg FROM DUAL");
$res = $mysqli->store_result();
var_dump($res->fetch_assoc());
?>
The above example will output:
proxy::storeResult(array (
0 => NULL,
))
proxy::storeResult returns NULL
resource(475) of type (Mysqlnd Resultset (internal only - you must not modify it!))
array(1) {
["_msg"]=>
string(27) "Also called buffered result"
}
proxy::storeResult(array (
0 => NULL,
))
proxy::storeResult returns NULL
resource(730) of type (Mysqlnd Resultset (internal only - you must not modify it!))
array(1) {
["_msg"]=>
string(13) "Good morning!"
}
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_store_result() - Transfers a result set from the last query
- mysqli_real_query() - Execute an SQL query
MysqlndUhConnection::txCommit
(PECL mysqlnd-uh >= 1.0.1-alpha)
MysqlndUhConnection::txCommit — Commits the current transaction
Description
$connection
) : boolCommits the current transaction.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::txCommit() example
<?php
class proxy extends MysqlndUhConnection {
public function txCommit($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::txCommit($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->commit();
?>
The above example will output:
proxy::txCommit(array (
0 => NULL,
))
proxy::txCommit returns true
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_commit() - Commits the current transaction
MysqlndUhConnection::txRollback
(PECL mysqlnd-uh >= 1.0.1-alpha)
MysqlndUhConnection::txRollback — Rolls back current transaction
Description
$connection
) : boolRolls back current transaction.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhConnection::txRollback() example
<?php
class proxy extends MysqlndUhConnection {
public function txRollback($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::txRollback($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->rollback();
?>
The above example will output:
proxy::txRollback(array (
0 => NULL,
))
proxy::txRollback returns true
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_commit() - Commits the current transaction
MysqlndUhConnection::useResult
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhConnection::useResult — Initiate a result set retrieval
Description
$connection
) : resourceInitiate a result set retrieval.
Parameters
-
connection -
Mysqlnd connection handle. Do not modify!
Return Values
Resource of type Mysqlnd Resultset (internal only - you must not modify it!).
The documentation may also refer to such resources using the alias name
mysqlnd_resultset.
Examples
Example #1 MysqlndUhConnection::useResult() example
<?php
class proxy extends MysqlndUhConnection {
public function useResult($res) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::useResult($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
var_dump($ret);
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->real_query("SELECT 'Good morning!' AS _msg FROM DUAL");
$res = $mysqli->use_result();
var_dump($res->fetch_assoc());
?>
The above example will output:
proxy::useResult(array (
0 => NULL,
))
proxy::useResult returns NULL
resource(425) of type (Mysqlnd Resultset (internal only - you must not modify it!))
array(1) {
["_msg"]=>
string(13) "Good morning!"
}
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
- mysqli_use_result() - Initiate a result set retrieval
- mysqli_real_query() - Execute an SQL query
Table of Contents
- MysqlndUhConnection::changeUser — Changes the user of the specified mysqlnd database connection
- MysqlndUhConnection::charsetName — Returns the default character set for the database connection
- MysqlndUhConnection::close — Closes a previously opened database connection
- MysqlndUhConnection::connect — Open a new connection to the MySQL server
- MysqlndUhConnection::__construct — The __construct purpose
- MysqlndUhConnection::endPSession — End a persistent connection
- MysqlndUhConnection::escapeString — Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection
- MysqlndUhConnection::getAffectedRows — Gets the number of affected rows in a previous MySQL operation
- MysqlndUhConnection::getErrorNumber — Returns the error code for the most recent function call
- MysqlndUhConnection::getErrorString — Returns a string description of the last error
- MysqlndUhConnection::getFieldCount — Returns the number of columns for the most recent query
- MysqlndUhConnection::getHostInformation — Returns a string representing the type of connection used
- MysqlndUhConnection::getLastInsertId — Returns the auto generated id used in the last query
- MysqlndUhConnection::getLastMessage — Retrieves information about the most recently executed query
- MysqlndUhConnection::getProtocolInformation — Returns the version of the MySQL protocol used
- MysqlndUhConnection::getServerInformation — Returns the version of the MySQL server
- MysqlndUhConnection::getServerStatistics — Gets the current system status
- MysqlndUhConnection::getServerVersion — Returns the version of the MySQL server as an integer
- MysqlndUhConnection::getSqlstate — Returns the SQLSTATE error from previous MySQL operation
- MysqlndUhConnection::getStatistics — Returns statistics about the client connection
- MysqlndUhConnection::getThreadId — Returns the thread ID for the current connection
- MysqlndUhConnection::getWarningCount — Returns the number of warnings from the last query for the given link
- MysqlndUhConnection::init — Initialize mysqlnd connection
- MysqlndUhConnection::killConnection — Asks the server to kill a MySQL thread
- MysqlndUhConnection::listFields — List MySQL table fields
- MysqlndUhConnection::listMethod — Wrapper for assorted list commands
- MysqlndUhConnection::moreResults — Check if there are any more query results from a multi query
- MysqlndUhConnection::nextResult — Prepare next result from multi_query
- MysqlndUhConnection::ping — Pings a server connection, or tries to reconnect if the connection has gone down
- MysqlndUhConnection::query — Performs a query on the database
- MysqlndUhConnection::queryReadResultsetHeader — Read a result set header
- MysqlndUhConnection::reapQuery — Get result from async query
- MysqlndUhConnection::refreshServer — Flush or reset tables and caches
- MysqlndUhConnection::restartPSession — Restart a persistent mysqlnd connection
- MysqlndUhConnection::selectDb — Selects the default database for database queries
- MysqlndUhConnection::sendClose — Sends a close command to MySQL
- MysqlndUhConnection::sendQuery — Sends a query to MySQL
- MysqlndUhConnection::serverDumpDebugInformation — Dump debugging information into the log for the MySQL server
- MysqlndUhConnection::setAutocommit — Turns on or off auto-committing database modifications
- MysqlndUhConnection::setCharset — Sets the default client character set
- MysqlndUhConnection::setClientOption — Sets a client option
- MysqlndUhConnection::setServerOption — Sets a server option
- MysqlndUhConnection::shutdownServer — The shutdownServer purpose
- MysqlndUhConnection::simpleCommand — Sends a basic COM_* command
- MysqlndUhConnection::simpleCommandHandleResponse — Process a response for a basic COM_* command send to the client
- MysqlndUhConnection::sslSet — Used for establishing secure connections using SSL
- MysqlndUhConnection::stmtInit — Initializes a statement and returns a resource for use with mysqli_statement::prepare
- MysqlndUhConnection::storeResult — Transfers a result set from the last query
- MysqlndUhConnection::txCommit — Commits the current transaction
- MysqlndUhConnection::txRollback — Rolls back current transaction
- MysqlndUhConnection::useResult — Initiate a result set retrieval
The MysqlndUhPreparedStatement class
(PECL mysqlnd-uh >= 1.0.0-alpha)
Introduction
Class synopsis
MysqlndUhPreparedStatement::__construct
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhPreparedStatement::__construct — The __construct purpose
Description
This function is currently not documented; only its argument list is available.
Parameters
This function has no parameters.
Return Values
MysqlndUhPreparedStatement::execute
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhPreparedStatement::execute — Executes a prepared Query
Description
$statement
) : boolExecutes a prepared Query.
Parameters
-
statement -
Mysqlnd prepared statement handle. Do not modify! Resource of type
Mysqlnd Prepared Statement (internal only - you must not modify it!).
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhPreparedStatement::execute() example
<?php
class stmt_proxy extends MysqlndUhPreparedStatement {
public function execute($res) {
printf("%s(", __METHOD__);
var_dump($res);
printf(")\n");
$ret = parent::execute($res);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
var_dump($ret);
return $ret;
}
}
mysqlnd_uh_set_statement_proxy(new stmt_proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$stmt = $mysqli->prepare("SELECT 'Labskaus' AS _msg FROM DUAL");
$stmt->execute();
$msg = NULL;
$stmt->bind_result($msg);
$stmt->fetch();
var_dump($msg);
?>
The above example will output:
stmt_proxy::execute(resource(256) of type (Mysqlnd Prepared Statement (internal only - you must not modify it!)) ) stmt_proxy::execute returns true bool(true) string(8) "Labskaus"
See Also
- mysqlnd_uh_set_statement_proxy() - Installs a proxy for mysqlnd statements
- mysqli_stmt_execute() - Executes a prepared Query
MysqlndUhPreparedStatement::prepare
(PECL mysqlnd-uh >= 1.0.0-alpha)
MysqlndUhPreparedStatement::prepare — Prepare an SQL statement for execution
Description
$statement
, string $query
) : boolPrepare an SQL statement for execution.
Parameters
-
statement -
Mysqlnd prepared statement handle. Do not modify! Resource of type
Mysqlnd Prepared Statement (internal only - you must not modify it!). -
query -
The query to be prepared.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 MysqlndUhPreparedStatement::prepare() example
<?php
class stmt_proxy extends MysqlndUhPreparedStatement {
public function prepare($res, $query) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$query = "SELECT 'No more you-know-what-I-mean for lunch, please' AS _msg FROM DUAL";
$ret = parent::prepare($res, $query);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
var_dump($ret);
return $ret;
}
}
mysqlnd_uh_set_statement_proxy(new stmt_proxy());
$mysqli = new mysqli("localhost", "root", "", "test");
$stmt = $mysqli->prepare("SELECT 'Labskaus' AS _msg FROM DUAL");
$stmt->execute();
$msg = NULL;
$stmt->bind_result($msg);
$stmt->fetch();
var_dump($msg);
?>
The above example will output:
stmt_proxy::prepare(array (
0 => NULL,
1 => 'SELECT \'Labskaus\' AS _msg FROM DUAL',
))
stmt_proxy::prepare returns true
bool(true)
string(46) "No more you-know-what-I-mean for lunch, please"
See Also
- mysqlnd_uh_set_statement_proxy() - Installs a proxy for mysqlnd statements
- mysqli_stmt_prepare() - Prepare an SQL statement for execution
- mysqli_prepare() - Prepare an SQL statement for execution
Table of Contents
- MysqlndUhPreparedStatement::__construct — The __construct purpose
- MysqlndUhPreparedStatement::execute — Executes a prepared Query
- MysqlndUhPreparedStatement::prepare — Prepare an SQL statement for execution
Mysqlnd_uh Functions
mysqlnd_uh_convert_to_mysqlnd
(PECL mysqlnd-uh >= 1.0.0-alpha)
mysqlnd_uh_convert_to_mysqlnd — Converts a MySQL connection handle into a mysqlnd connection handle
Description
Converts a MySQL connection handle into a mysqlnd connection handle. After conversion you can execute mysqlnd library calls on the connection handle. This can be used to access mysqlnd functionality not made available through user space API calls.
The function can be disabled with
mysqlnd_uh.enable.
If mysqlnd_uh.enable
is set to FALSE the function will not install the proxy and
always return TRUE. Additionally, an error of the
type E_WARNING may be emitted. The error message may
read like PHP Warning: mysqlnd_uh_convert_to_mysqlnd(): (Mysqlnd User Handler)
The plugin has been disabled by setting the configuration parameter mysqlnd_uh.enable = false.
You are not allowed to call this function [...].
Parameters
-
MySQL connection handle -
A MySQL connection handle of type mysql, mysqli or PDO_MySQL.
Return Values
A mysqlnd connection handle.
Changelog
| Version | Description |
|---|---|
| 5.4.0 |
The mysql_connection parameter can now be of type
mysql, PDO_MySQL, or mysqli.
Before, only the mysqli type was allowed.
|
Examples
Example #1 mysqlnd_uh_convert_to_mysqlnd() example
<?php
/* PDO user API gives no access to connection thread id */
$mysql_connection = new PDO("mysql:host=localhost;dbname=test", "root", "");
/* Convert PDO MySQL handle to mysqlnd handle */
$mysqlnd = mysqlnd_uh_convert_to_mysqlnd($mysql_connection);
/* Create Proxy to call mysqlnd connection class methods */
$obj = new MySQLndUHConnection();
/* Call mysqlnd_conn::get_thread_id */
var_dump($obj->getThreadId($mysqlnd));
/* Use SQL to fetch connection thread id */
var_dump($mysql_connection->query("SELECT CONNECTION_ID()")->fetchAll());
?>
The above example will output:
int(27054)
array(1) {
[0]=>
array(2) {
["CONNECTION_ID()"]=>
string(5) "27054"
[0]=>
string(5) "27054"
}
}
mysqlnd_uh_set_connection_proxy
(PECL mysqlnd-uh >= 1.0.0-alpha)
mysqlnd_uh_set_connection_proxy — Installs a proxy for mysqlnd connections
Description
&$connection_proxy
[, mysqli &$mysqli_connection
] ) : boolInstalls a proxy object to hook mysqlnd's connection objects methods. Once installed, the proxy will be used for all MySQL connections opened with mysqli, mysql or PDO_MYSQL, assuming that the listed extensions are compiled to use the mysqlnd library.
The function can be disabled with
mysqlnd_uh.enable.
If mysqlnd_uh.enable
is set to FALSE the function will not install the proxy and
always return TRUE. Additionally, an error of the
type E_WARNING may be emitted. The error message may
read like PHP Warning: mysqlnd_uh_set_connection_proxy(): (Mysqlnd User Handler)
The plugin has been disabled by setting the configuration parameter mysqlnd_uh.enable = false.
The proxy has not been installed [...].
Parameters
-
connection_proxy -
A proxy object of type MysqlndUhConnection.
-
mysqli_connection -
Object of type
mysqli. If given, the proxy will be set for this particular connection only.
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
Examples
Example #1 mysqlnd_uh_set_connection_proxy() example
<?php
$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->query("SELECT 'No proxy installed, yet'");
class proxy extends MysqlndUhConnection {
public function query($res, $query) {
printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
$ret = parent::query($res, $query);
printf("%s returns %s\n", __METHOD__, var_export($ret, true));
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli->query("SELECT 'mysqlnd rocks!'");
$mysql = mysql_connect("localhost", "root", "", "test");
mysql_query("SELECT 'Ahoy Andrey!'", $mysql);
$pdo = new PDO("mysql:host=localhost;dbname=test", "root", "");
$pdo->query("SELECT 'Moin Johannes!'");
?>
The above example will output:
proxy::query(array (
0 => NULL,
1 => 'SELECT \'mysqlnd rocks!\'',
))
proxy::query returns true
proxy::query(array (
0 => NULL,
1 => 'SELECT \'Ahoy Andrey!\'',
))
proxy::query returns true
proxy::query(array (
0 => NULL,
1 => 'SELECT \'Moin Johannes!\'',
))
proxy::query returns true
See Also
- mysqlnd_uh_set_statement_proxy() - Installs a proxy for mysqlnd statements
-
mysqlnd_uh.enable
mysqlnd_uh_set_statement_proxy
(PECL mysqlnd-uh >= 1.0.0-alpha)
mysqlnd_uh_set_statement_proxy — Installs a proxy for mysqlnd statements
Description
&$statement_proxy
) : boolInstalls a proxy for mysqlnd statements. The proxy object will be used for all mysqlnd prepared statement objects, regardless which PHP MySQL extension (mysqli, mysql, PDO_MYSQL) has created them as long as the extension is compiled to use the mysqlnd library.
The function can be disabled with
mysqlnd_uh.enable.
If mysqlnd_uh.enable
is set to FALSE the function will not install the proxy and
always return TRUE. Additionally, an error of the
type E_WARNING may be emitted. The error message may
read like PHP Warning: mysqlnd_uh_set_statement_proxy(): (Mysqlnd User Handler)
The plugin has been disabled by setting the configuration parameter mysqlnd_uh.enable = false.
The proxy has not been installed [...].
Parameters
-
statement_proxy -
The mysqlnd statement proxy object of type
MysqlndUhStatement
Return Values
Returns TRUE on success.
Otherwise, returns FALSE
See Also
- mysqlnd_uh_set_connection_proxy() - Installs a proxy for mysqlnd connections
-
mysqlnd_uh.enable
Table of Contents
- mysqlnd_uh_convert_to_mysqlnd — Converts a MySQL connection handle into a mysqlnd connection handle
- mysqlnd_uh_set_connection_proxy — Installs a proxy for mysqlnd connections
- mysqlnd_uh_set_statement_proxy — Installs a proxy for mysqlnd statements
Change History
Table of Contents
The Change History lists major changes users need to be aware if upgrading from one version to another. It is a high level summary of selected changes that may impact applications or might even break backwards compatibility. See also the CHANGES file contained in the source for additional changelog information. The commit history is also available.
PECL/mysqlnd_uh 1.0 series
1.0.1-alpha
- Release date: TBD
- Motto/theme: bug fix release
Feature changes
- Support of PHP 5.4.0 or later.
-
BC break: MysqlndUhConnection::changeUser() requires
additional
passwd_lenparameter. -
BC break:
MYSQLND_UH_VERSION_STRrenamed toMYSQLND_UH_VERSION.MYSQLND_UH_VERSIONrenamed toMYSQLND_UH_VERSION_ID. -
BC break:
mysqlnd_uh.enabledconfiguration setting renamed tomysqlnd_uh.enable.
1.0.0-alpha
- Release date: 08/2010
- Motto/theme: Initial release
- Introduction
- Quickstart and Examples
- Installing/Configuring
- Predefined Constants
- MysqlndUhConnection — The MysqlndUhConnection class
- MysqlndUhConnection::changeUser — Changes the user of the specified mysqlnd database connection
- MysqlndUhConnection::charsetName — Returns the default character set for the database connection
- MysqlndUhConnection::close — Closes a previously opened database connection
- MysqlndUhConnection::connect — Open a new connection to the MySQL server
- MysqlndUhConnection::__construct — The __construct purpose
- MysqlndUhConnection::endPSession — End a persistent connection
- MysqlndUhConnection::escapeString — Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection
- MysqlndUhConnection::getAffectedRows — Gets the number of affected rows in a previous MySQL operation
- MysqlndUhConnection::getErrorNumber — Returns the error code for the most recent function call
- MysqlndUhConnection::getErrorString — Returns a string description of the last error
- MysqlndUhConnection::getFieldCount — Returns the number of columns for the most recent query
- MysqlndUhConnection::getHostInformation — Returns a string representing the type of connection used
- MysqlndUhConnection::getLastInsertId — Returns the auto generated id used in the last query
- MysqlndUhConnection::getLastMessage — Retrieves information about the most recently executed query
- MysqlndUhConnection::getProtocolInformation — Returns the version of the MySQL protocol used
- MysqlndUhConnection::getServerInformation — Returns the version of the MySQL server
- MysqlndUhConnection::getServerStatistics — Gets the current system status
- MysqlndUhConnection::getServerVersion — Returns the version of the MySQL server as an integer
- MysqlndUhConnection::getSqlstate — Returns the SQLSTATE error from previous MySQL operation
- MysqlndUhConnection::getStatistics — Returns statistics about the client connection
- MysqlndUhConnection::getThreadId — Returns the thread ID for the current connection
- MysqlndUhConnection::getWarningCount — Returns the number of warnings from the last query for the given link
- MysqlndUhConnection::init — Initialize mysqlnd connection
- MysqlndUhConnection::killConnection — Asks the server to kill a MySQL thread
- MysqlndUhConnection::listFields — List MySQL table fields
- MysqlndUhConnection::listMethod — Wrapper for assorted list commands
- MysqlndUhConnection::moreResults — Check if there are any more query results from a multi query
- MysqlndUhConnection::nextResult — Prepare next result from multi_query
- MysqlndUhConnection::ping — Pings a server connection, or tries to reconnect if the connection has gone down
- MysqlndUhConnection::query — Performs a query on the database
- MysqlndUhConnection::queryReadResultsetHeader — Read a result set header
- MysqlndUhConnection::reapQuery — Get result from async query
- MysqlndUhConnection::refreshServer — Flush or reset tables and caches
- MysqlndUhConnection::restartPSession — Restart a persistent mysqlnd connection
- MysqlndUhConnection::selectDb — Selects the default database for database queries
- MysqlndUhConnection::sendClose — Sends a close command to MySQL
- MysqlndUhConnection::sendQuery — Sends a query to MySQL
- MysqlndUhConnection::serverDumpDebugInformation — Dump debugging information into the log for the MySQL server
- MysqlndUhConnection::setAutocommit — Turns on or off auto-committing database modifications
- MysqlndUhConnection::setCharset — Sets the default client character set
- MysqlndUhConnection::setClientOption — Sets a client option
- MysqlndUhConnection::setServerOption — Sets a server option
- MysqlndUhConnection::shutdownServer — The shutdownServer purpose
- MysqlndUhConnection::simpleCommand — Sends a basic COM_* command
- MysqlndUhConnection::simpleCommandHandleResponse — Process a response for a basic COM_* command send to the client
- MysqlndUhConnection::sslSet — Used for establishing secure connections using SSL
- MysqlndUhConnection::stmtInit — Initializes a statement and returns a resource for use with mysqli_statement::prepare
- MysqlndUhConnection::storeResult — Transfers a result set from the last query
- MysqlndUhConnection::txCommit — Commits the current transaction
- MysqlndUhConnection::txRollback — Rolls back current transaction
- MysqlndUhConnection::useResult — Initiate a result set retrieval
- MysqlndUhPreparedStatement — The MysqlndUhPreparedStatement class
- MysqlndUhPreparedStatement::__construct — The __construct purpose
- MysqlndUhPreparedStatement::execute — Executes a prepared Query
- MysqlndUhPreparedStatement::prepare — Prepare an SQL statement for execution
- Mysqlnd_uh Functions
- mysqlnd_uh_convert_to_mysqlnd — Converts a MySQL connection handle into a mysqlnd connection handle
- mysqlnd_uh_set_connection_proxy — Installs a proxy for mysqlnd connections
- mysqlnd_uh_set_statement_proxy — Installs a proxy for mysqlnd statements
- Change History
Mysqlnd connection multiplexing plugin
Introduction
The mysqlnd multiplexing plugin (mysqlnd_mux)
multiplexes MySQL connections established by all PHP MySQL extensions
that use the MySQL native driver (mysqlnd)
for PHP.
The MySQL native driver for PHP features an internal C API for plugins, such as the connection multiplexing plugin, which can extend the functionality of mysqlnd. See the mysqlnd for additional details about its benefits over the MySQL Client Library libmysqlclient.
Mysqlnd plugins like mysqlnd_mux operate, for the most part,
transparently from a user perspective. The connection multiplexing
plugin supports all PHP applications, and all MySQL PHP extensions.
It does not change existing APIs. Therefore, it can easily be used with
existing PHP applications.
Note:
This is a proof-of-concept. All features are at an early stage. Not all kinds of queries are handled by the plugin yet. Thus, it cannot be used in a drop-in fashion at the moment.
Please, do not use this version in production environments.
Key Features
The key features of mysqlnd_mux are as follows:
-
Transparent and therefore easy to use:
-
Supports all of the PHP MySQL extensions.
-
Little to no application changes are required, dependent on the required usage scenario.
-
-
Reduces server load and connection establishment latency:
-
Opens less connections to the MySQL server.
-
Less connections to MySQL mean less work for the MySQL server. In a client-server environment scaling the server is often more difficult than scaling the client. Multiplexing helps with horizontal scale-out (scale-by-client).
-
Pooling saves connection time.
-
Multiplexed connection: multiple user handles share the same network connection. Once opened, a network connection is cached and shared among multiple user handles. There is a 1:n relationship between internal network connection and user connection handles.
-
Persistent connection: a network connection is kept open at the end of the web request, if the PHP deployment model allows. Thus, subsequently web requests can reuse a previously opened connection. Like other resources, network connections are bound to the scope of a process. Thus, they can be reused for all web requests served by a process.
-
Limitations
The proof-of-concept does not support unbuffered queries, prepared statements, and asynchronous queries.
The connection pool is using a combination of the transport method and hostname as keys. As a consequence, two connections to the same host using the same transport method (TCP/IP, Unix socket, Windows named pipe) will be linked to the same pooled connection even if username and password differ. Be aware of the possible security implications.
The proof-of-concept is transaction agnostic. It does not know about SQL transactions.
Note:
Applications must be aware of the consequences of connection sharing connections.
About the name mysqlnd_mux
The shortcut mysqlnd_mux
stands for mysqlnd connection multiplexing plugin.
Concepts
Table of Contents
This explains the architecture and related concepts for this plugin. Reading and understanding these concepts is required to successfully use this plugin.
Architecture
The mysqlnd connection multiplexing plugin is implemented as a PHP extension. It is written in C and operates under the hood of PHP. During the startup of the PHP interpreter, in the module initialization phase of the PHP engine, it gets registered as a mysqlnd plugin to replace specific mysqlnd C methods.
The mysqlnd library uses PHP streams to communicate with the MySQL server. PHP streams are accessed by the mysqlnd library through its net module. The mysqlnd connection multiplexing plugin proxies methods of the mysqlnd library net module to control opening and closing of network streams.
Upon opening a user connection to MySQL using the appropriate connection functions of either mysqli, PDO_MYSQL or ext/mysql, the plugin will search its connection pool for an open network connection. If the pool contains a network connection to the host specified by the connect function using the transport method requested (TCP/IP, Unix domain socket, Windows named pipe), the pooled connection is linked to the user handle. Otherwise, a new network connection is opened, put into the poolm and associated with the user connection handle. This way, multiple user handles can be linked to the same network connection.
Connection pool
The plugins connection pool is created when PHP initializes its modules
(MINIT) and free'd when PHP shuts down the modules
(MSHUTDOWN). This is the same as for persistent MySQL connections.
Depending on the deployment model, the pool is used for the duration of one or multiple web requests. Network connections are bound to the lifespan of an operating system level process. If the PHP process serves multiple web requests as it is the case for Fast-CGI or threaded web server deployments, then the pooled connections can be reused over multiple connections. Because multiplexing means sharing connections, it can even happen with a threaded deployment that two threads or two distinct web requests are linked to one pooled network connections.
A pooled connection is explicitly closed once the last reference to it is released. An implicit close happens when PHP shuts down its modules.
Sharing connections
The PHP mysqlnd connection multiplexing plugin changes the relationship between a users connection handle and the underlying MySQL connection. Without the plugin, every MySQL connection belongs to exactly one user connection at a time. The multiplexing plugin changes. A MySQL connection is shared among multiple user handles. There no one-to-one relation if using the plugin.
Sharing pooled connections has an impact on the connection state. State changing operations from multiple user handles pointing to one MySQL connection are not isolated from each other. If, for example, a session variable is set through one user connection handle, the session variable becomes visible to all other user handles that reference the same underlying MySQL connection.
This is similar in concept to connection state related phenomens described for the PHP mysqlnd replication and load balancing plugin. Please, check the PECL/mysqlnd_ms documentation for more details on the state of a connection.
The proof-of-concept takes no measures to isolate multiplexed connections from each other.
Installing/Configuring
Table of Contents
Requirements
PHP 5.5.0 or newer.
Some advanced functionality requires PHP 5.5.0 or newer.
The mysqlnd_mux replication and load balancing
plugin supports all PHP applications and all available PHP MySQL extensions
(mysqli,
mysql,
PDO_MYSQL).
The PHP MySQL extension must be configured to use
mysqlnd in order to be able
to use the mysqlnd_mux plugin for
mysqlnd.
Installation
Information for installing this PECL extension may be found in the manual chapter titled Installation of PECL extensions. Additional information such as new releases, downloads, source files, maintainer information, and a CHANGELOG, can be located here: » https://pecl.php.net/package/mysqlnd_mux
Runtime Configuration
The behaviour of these functions is affected by settings in php.ini.
| Name | Default | Changeable | Changelog |
|---|---|---|---|
| mysqlnd_mux.enable | 0 | PHP_INI_SYSTEM |
Here's a short explanation of the configuration directives.
Predefined Constants
The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
Other
The plugins version number can be obtained using
MYSQLND_MUX_VERSION or
MYSQLND_MUX_VERSION_ID.
MYSQLND_MUX_VERSION
is the string representation of the numerical version number
MYSQLND_MUX_VERSION_ID, which is an integer such as 10000.
Developers can calculate the version number as follows.
| Version (part) | Example |
|---|---|
| Major*10000 | 1*10000 = 10000 |
| Minor*100 | 0*100 = 0 |
| Patch | 0 = 0 |
| MYSQLND_MUX_VERSION_ID | 10000 |
Change History
Table of Contents
This change history is a high level summary of selected changes that may impact applications and/or break backwards compatibility.
See also the CHANGES file in the source distribution for a complete list of changes.
PECL/mysqlnd_mux 1.0 series
1.0.0-pre-alpha
- Release date: no package released, initial check-in 09/2012
- Motto/theme: Proof of concept
Initial check-in. Essentially a demo of the mysqlnd plugin API.
Note:
This is the current development series. All features are at an early stage. Changes may happen at any time without prior notice. Please, do not use this version in production environments.
The documentation may not reflect all changes yet.
Mysqlnd Memcache plugin
Introduction
The mysqlnd memcache plugin (mysqlnd_memcache) is an PHP
extension for transparently translating SQL into requests for the
MySQL InnoDB Memcached Daemon Plugin (server plugin). It includes
experimental support for the MySQL Cluster Memcached Daemon. The server
plugin provides access to data stored inside MySQL InnoDB (respectively
MySQL Cluster NDB) tables using the Memcache protocol.
This PHP extension, which supports all PHP MySQL extensions that use
mysqlnd, will identify tables exported in
this way and will translate specific SELECT queries into Memcache requests.
Note:
This plugin depends on the MySQL InnoDB Memcached Daemon Plugin. It is not provided to be used with a stand-alone Memcached. For a generic query cache using Memcached look at the mysqlnd query cache plugin. For direct Memcache access look at the memcache and memcached extensions.
The MySQL native driver for PHP is a C library that ships together with PHP as of PHP 5.3.0. It serves as a drop-in replacement for the MySQL Client Library (libmysqlclient). Using mysqlnd has several advantages: no extra downloads are required because it's bundled with PHP, it's under the PHP license, there is lower memory consumption in certain cases, and it contains new functionality such as asynchronous queries.
The mysqlnd_mmemcache operates, for the most part,
transparently from a user perspective. The mysqlnd memcache
plugin supports all PHP applications, and all MySQL PHP extensions.
It does not change existing APIs. Therefore, it can easily be used with
existing PHP applications.
The MySQL Memcache plugins add key-value style access method for data stored in InnoDB resp. NDB (MySQL Cluster) SQL tables through the Memcache protocol. This type of key-value access if often faster than using SQL.
Key Features
The key features of PECL/mysqlnd_memcache are as follows.
-
Possible performance benefits
-
Client-side: light-weight protocol.
-
Server-side: no SQL parsing, direct access to the storage.
-
Please, run your own benchmarks! Actual performance results are highly dependent on setup and hardware used.
-
Limitations
The initial version is not binary safe. Due to the way the MySQL Memcache plugins works there are restrictions related to separators.
Prepared statements and asynchronous queries are not supported. Result set meta data support is limited.
The mapping information for tables accessible via Memcache is not cached in the plugin between requests but fetched from the MySQL server each time a MySQL connection is associated with a Memcache connection. See mysqlnd_memcache_set() for details.
On the name
The shortcut mysqlnd_memcache
stands for mysqlnd memcache plugin.
Memcache refers to support of the MySQL Memcache plugins
for InnoDB and NDB (MySQL Cluster). The plugin is not
related to the Memcached cache server.
Quickstart and Examples
Table of Contents
The mysqlnd memcache plugin is easy to use. This quickstart will demo typical use-cases, and provide practical advice on getting started.
It is strongly recommended to read the reference sections in addition to the quickstart. The quickstart tries to avoid discussing theoretical concepts and limitations. Instead, it will link to the reference sections. It is safe to begin with the quickstart. However, before using the plugin in mission critical environments we urge you to read additionally the background information from the reference sections.
Setup
The plugin is implemented as a PHP extension. See also the installation instructions to install this extension.
Compile or configure the PHP MySQL extension (API) (mysqli, PDO_MYSQL, mysql). That extension must use the mysqlnd library as because mysqlnd_memcache is a plugin for the mysqlnd library. For additional information, refer to the mysqlnd_memcache installation instructions.
Then, load this extension into PHP and activate the plugin in the PHP configuration file using the PHP configuration directive named mysqlnd_memcache.enable.
Example #1 Enabling the plugin (php.ini)
; On Windows the filename is php_mysqnd_memcache.dll ; Load the extension extension=mysqlnd_memcache.so ; Enable it mysqlnd_memcache.enable=1
Follow the instructions given in the » MySQL Reference Manual on installing the Memcache plugins for the MySQL server. Activate the plugins and configure Memcache access for SQL tables.
The examples in this quickguide assume that the following table exists, and that Memcache is configured with access to it.
Example #2 SQL table used for the Quickstart
CREATE TABLE test(
id CHAR(16),
f1 VARCHAR(255),
f2 VARCHAR(255),
f3 VARCHAR(255),
flags INT NOT NULL,
cas_column INT,
expire_time_column INT,
PRIMARY KEY(id)
) ENGINE=InnoDB;
INSERT INTO test (id, f1, f2, f3) VALUES (1, 'Hello', 'World', '!');
INSERT INTO test (id, f1, f2, f3) VALUES (2, 'Lady', 'and', 'the tramp');
INSERT INTO innodb_memcache.containers(
name, db_schema, db_table, key_columns, value_columns,
flags, cas_column, expire_time_column, unique_idx_name_on_key)
VALUES (
'plugin_test', 'test', 'test', 'id', 'f1,f2,f3',
'flags', 'cas_column', 'expire_time_column', 'PRIMARY KEY');
Usage
After associating a MySQL connection with a Memcache connection using
mysqnd_memcache_set() the plugin attempts to transparently
replace SQL SELECT
statements by a memcache access. For that purpose the plugin monitors
all SQL statements executed and tries to match the statement string
against MYSQLND_MEMCACHE_DEFAULT_REGEXP.
In case of a match, the mysqlnd memcache plugin checks whether the
SELECT is accessing only columns of a mapped table and
the WHERE clause is limited to a single key lookup.
In case of the example SQL table, the plugin will use the Memcache interface
of the MySQL server to fetch results for a SQL query like
SELECT f1, f2, f3 WHERE id = n.
Example #1 Basic example.
<?php
$mysqli = new mysqli("host", "user", "passwd", "database");
$memc = new Memcached();
$memc->addServer("host", 11211);
mysqlnd_memcache_set($mysqli, $memc);
/*
This is a query which queries table test using id as key in the WHERE part
and is accessing fields f1, f2 and f3. Therefore, mysqlnd_memcache
will intercept it and route it via memcache.
*/
$result = $mysqli->query("SELECT f1, f2, f3 FROM test WHERE id = 1");
while ($row = $result->fetch_row()) {
print_r($row);
}
/*
This is a query which queries table test but using f1 in the WHERE clause.
Therefore, mysqlnd_memcache can't intercept it. This will be executed
using the MySQL protocol
*/
$mysqli->query("SELECT id FROM test WHERE f1 = 'Lady'");
while ($row = $result->fetch_row()) {
print_r($row);
}
?>
The above example will output:
array(
[f1] => Hello
[f2] => World
[f3] => !
)
array(
[id] => 2
)